1993 OMC 5.8 EFI and drive system conversion to Volvo Penta

[Rhc]

I have owned this boat and OMC motor drive system since new. The model is 58FAVRJVN serial T01255989. I find it more difficult to adjust the interrupters and cables to retain easy shift changes. I am considering information from https://www.marinepartsexpress.com/PDF/volvo/SX_Cobra.pdf. This deals with conversion to Volvo SX Or possibility DP R? It looks reasonably straightforward. I understand the purchase of a motor mounted water pump is required, is that available? My engine/drive is pristine and has about 475 hours. I’ve done my own maintenance.
I would like to make the shifting much easier and understand the cone drive system by Volvo will accomplish this? Although it is a consideration, the motor electronic control module is not available anymore, I am banking on the EMC to be reliable so changing the engine is not likely an option given its low hours in top condition?? Can you advise me on the feasibility of conversion, cautions and material costs. Is it better to locate a USED Volvo compatible drive and a new “helmet” for drive fit up to OMC transom? Hope some can help —- Rhc

 

[Lou C]

This has been done, and V/P also used that same 5.8 Ford engine on the early years of the SX model. If the shift cable is in good shape (low drag) and adjusted properly, the drive lower unit is in good shape (gears and clutch dog as well as shifter mechanism inside) the original Cobra with dog clutch shifting can shift VERY well, mine does and has only needed a few repairs over the years. If you can't do it yourself though then it can be very tough to find someone who knows how to set these up right.
So that's where the conversion might make sense but only if you can do it with used parts, and a reman drive. Otherwise way too expensive. There are other details that go along with it, one you have to add a crankshaft mounted raw water pump, the other is you may need to add spacers inside the trim rams to keep the drive from raising up too high when trimmed all the way up, and there was also some issue I recall mentioned with the trim ram rod/bushings. Not sure what the solution to that was.
The engine issue with the ECM, is something else, that has a system that there are no parts for except used. The best way to deal with it is to convert it to a conventional carb set up. Simple, parts are everywhere (Holley 4160 4bbl) that's what was used before they went to this "improved" efi system. I would not spend a nickel on that EFI system, too many parts are NLA. You'd need a Ford 4 bbl intake for the 5.8, the carb and see if you can use a mechancial Carter fuel pump. The carb, and pump can be bought new, the intake you'd have to get used, from Ebay. Another complication is the distributor, you'd have to find a marine unit that can work with out that ECM. Earlier models used a Prestolite points unit. Might be able to find that on ebay as well....Hardin Marine sells a Petonix marine distributor for this engine, that would nicely solve that problem.
So if you convert to the SX and run it till you have an issue with the ECM/EFI, you have options to make the engine maintain-able with aftermarket parts, and not have to worry about all the NLA OMC stuff.
Not a simple job as you can see...make sure the boat is really worth it.
My way of dealing with this is that I have a lot of spares, spare drive, transom mount, and all related parts (trim pump, power steering actuator, pump, exhaust Y pipe, etc anything that can't be found easily). The shift cable adjustment I taught myself to do about 10 years ago, I adjusted it once and it's been fine ever since. The key to this job is not to take short cuts, make sure each step is done right, then keep the engine in good enough tune so it will run reliably at 600 rpm and not stall when the ESA lowers the idle to 450 to shift out of gear. Doing these things mine shifts with 2 fingers almost as smooth as a Volvo, is quiet, no odd noises, etc. The rest of the boat (wood rot) gave me fits, the OMC stuff I have not had much trouble with at all, surprising I know.

 

[Rhc]

This has been done, and V/P also used that same 5.8 Ford engine on the early years of the SX model. If the shift cable is in good shape (low drag) and adjusted properly, the drive lower unit is in good shape (gears and clutch dog as well as shifter mechanism inside) the original Cobra with dog clutch shifting can shift VERY well, mine does and has only needed a few repairs over the years. If you can't do it yourself though then it can be very tough to find someone who knows how to set these up right.
So that's where the conversion might make sense but only if you can do it with used parts, and a reman drive. Otherwise way too expensive. There are other details that go along with it, one you have to add a crankshaft mounted raw water pump, the other is you may need to add spacers inside the trim rams to keep the drive from raising up too high when trimmed all the way up, and there was also some issue I recall mentioned with the trim ram rod/bushings. Not sure what the solution to that was.
The engine issue with the ECM, is something else, that has a system that there are no parts for except used. The best way to deal with it is to convert it to a conventional carb set up. Simple, parts are everywhere (Holley 4160 4bbl) that's what was used before they went to this "improved" efi system. I would not spend a nickel on that EFI system, too many parts are NLA. You'd need a Ford 4 bbl intake for the 5.8, the carb and see if you can use a mechancial Carter fuel pump. The carb, and pump can be bought new, the intake you'd have to get used, from Ebay. Another complication is the distributor, you'd have to find a marine unit that can work with out that ECM. Earlier models used a Prestolite points unit. Might be able to find that on ebay as well....
Not a simple job as you can see...make sure the boat is really worth it.

So glad to find a subject matter expert! Your details are great and very helpful. I have assumed the shift difficulty was due to set up of interrupter switches? This is usually where I check the cable lengths etc. Would I be better to consider the lower drive -- it seems you can buy a new or reman for about $ 1500 or say less than 2k? I have opened up my lower drive and did not seen excessive wear. I did have a senior tech look over the pieces and he did not see a problem. I am not sure if that information was good and it was from 4/5 years ago so things could have changed. Can I trust the parts source company's on line? Do you have a recommendation for replacement drives? New or renan? Used sounds to risky given the difficulty to rework locally. Is the difficult shift changing more likely to be the in drive. It could be least expensive option and hope for the best on the rest? I expect to use the boat for less than the next 5-7 years max due to my age. Is a used motor/drive change out to a used set would likely to cost 10k + ? Not sure if that would be justified? Before I do anything I wait to here your input. If required could we exchange phone numbers?? Thanks again.

 

[Lou C]

It depends on what shifting difficulty you are having....not going into gear....popping out of gear....or not coming out of gear. The last is the most common problem.
To start, the adjustment process begins with the drive off. You check the shift rod height against factory specs, and make sure it shifts from N, to FWD, to REV without too much effort.
Next the shift cable gets disconnected at the shifter bellcrank and up on the engine bracket. You measure the drag in both directions, with a fish scale. It should not exceed 2.5 lbs.
While you're there, clean out the pocket where the shifter bellcrank lives, you can get crud in there that jams up the bellcrank and causes difficult shifting.
Next you adjust the transom shift cables using the 2 special OMC tools to ensure proper adjustment. Then re-install the drive, and adjust the remote cable. You want equal travel on both sides of neutral.
Lastly make sure the ESA system works, it should only be triggered when shifting out of gear with the boat in the water with a load on the prop.
This is a very abbreviated version of what you have to do, I'm not sure if you covered all these points in the past, but that's basically it.
As far as where to get parts, and reman drives I don't really know, I used a local mechanic who was great but they retired. I like TCI Electronics/Marine in Canada, I called them to discuss rebuilding my spare drive and they obviously know this drivesystem. If I need a reman I will probably use them.
For regular parts I’ve used marine engine dot com, and Crowley marine dot com. For NLA parts, I use NLA marine & eBay.

 

[Rhc]

So glad to find a subject matter expert! Your details are great and very helpful. I have assumed the shift difficulty was due to set up of interrupter switches? This is usually where I check the cable lengths etc. Would I be better to consider the lower drive -- it seems you can buy a new or reman for about $ 1500 or say less than 2k? I have opened up my lower drive and did not seen excessive wear. I did have a senior tech look over the pieces and he did not see a problem. I am not sure if that information was good and it was from 4/5 years ago so things could have changed. Can I trust the parts source company's on line? Do you have a recommendation for replacement drives? New or renan? Used sounds to risky given the difficulty to rework locally. Is the difficult shift changing more likely to be the in drive. It could be least expensive option and hope for the best on the rest? I expect to use the boat for less than the next 5-7 years max due to my age. Is a used motor/drive change out to a used set would likely to cost 10k + ? Not sure if that would be justified? Before I do anything I wait to here your input. If required could we exchange phone numbers?? Thanks again.

So glad to find a subject matter expert! Your details are great and very helpful. I have assumed the shift difficulty was due to set up of interrupter switches? This is usually where I check the cable lengths etc. Would I be better to consider the lower drive -- it seems you can buy a new or reman for about $ 1500 or say less than 2k? I have opened up my lower drive and did not seen excessive wear. I did have a senior tech look over the pieces and he did not see a problem. I am not sure if that information was good and it was from 4/5 years ago so things could have changed. Can I trust the parts source company's on line? Do you have a recommendation for replacement drives? New or renan? Used sounds to risky given the difficulty to rework locally. Is the difficult shift changing more likely to be the in drive. It could be least expensive option and hope for the best on the rest? I expect to use the boat for less than the next 5-7 years max due to my age. Is a used motor/drive change out to a used set would likely to cost 10k + ? Not sure if that would be justified? Before I do anything I wait to here your input. If required could we exchange phone numbers?? Thanks again.

Your input is excellent and very accurate . Thank you. My main problem occurs when docking the shift will not move from forward to reverse without significant pulling. Similarity when I go from reverse to forward it is a restrictive motion. Do cables stretch that much and in some 3 year time line?
My first action will be to measure the selector shaft height As you indicated. I believe I have managed to complete all the other tests in the past as you have suggested. I have the original OMC manuals that came with the drive. These manuals do cover in detail the settings that you indicated. I will double check but was done three years ago. Should these settings move that quickly?
I’m not sure that I have checked the shaft height you referred to, so will start there.
I have confirmed the lower drive is available from your recommendation at TCI electronics for about $1600. Now how do I determine if the lower drive set up and condition could be the underlying problem? What would I look for in the drive to determine its condition?

 

[Lou C]

You should always hesitate in neutral when shifting from Fwd to Rev & vice versa. Check to make sure that the ESA system is lowering the idle speed when you shift from Fwd or Rev to neutral. Your normal idle should not be higher than 600 rpm in gear. If you trigger the ESA interrupt switch is should lower the idle to 450 rpm. If not you will have the problem you describe. The adjustments don’t change but the cables can wear and get stiff or they can stretch if you have to force it out of gear. A properly adjusted Cobra with functioning ESA & good cables & proper idle speed will shift to neutral with just 2 finger pressure on the control. Mind does…

 

[Rhc]

You should always hesitate in neutral when shifting from Fwd to Rev & vice versa. Check to make sure that the ESA system is lowering the idle speed when you shift from Fwd or Rev to neutral. Your normal idle should not be higher than 600 rpm in gear. If you trigger the ESA interrupt switch is should lower the idle to 450 rpm. If not you will have the problem you describe. The adjustments don’t change but the cables can wear and get stiff or they can stretch if you have to force it out of gear. A properly adjusted Cobra with functioning ESA & good cables & proper idle speed will shift to neutral with just 2 finger pressure on the control. Mind does…

I did take your advice in your last thread, where you talked about going to TCI electronics submarines in Toronto. The drive has been rebuilt for the lower half. Generally, there was very little wrong with the drive although we did replace the clutch dog and machine the inside of the Ford and reverse gears for better activation. Now, I am confused on the ESA operation. I have been told that the interrupter is normally open and the over stroke is normally closed. I’m not sure if this is correct.
Just to refresh your memory if you don’t wanna go back in this thread, I have a 1993 OMC cobra 5.8 L. I do not have or can open your images of the wiring diagram for ESA , interrupter, over stroke switches. I need clarification on the switches being normally open or normally closed. Both micro switches are labeled NO with wires on C and NO TERMINALS.
To clarify the interrupter switch with roller in V the ohm meter is at infinity. When roller is at top of interrupter the meter is zero or continuity is achieved. Is this as you expect?
The overstroke switch in neutral is at zero or continuity. When the over stroke switch is in forward or reverse there is no continuity it’s opened or at infinity. Is this as you expect?
All is working for shift but going from in gear to neutral requires a pause and jiggle before it will disengage gear. Is this as expected.
Lower drive has been disassembled and rebuilt. All cables have been replaced. The wiring is original as I’ve had the boat since new but never been totally happy with the shifting. Is the original wiring incorrect?
Thanks Bob

 

[Rhc]

I did take your advice in your last thread, where you talked about going to TCI electronics submarines in Toronto. The drive has been rebuilt for the lower half. Generally, there was very little wrong with the drive although we did replace the clutch dog and machine the inside of the Ford and reverse gears for better activation. Now, I am confused on the ESA operation. I have been told that the interrupter is normally open and the over stroke is normally closed. I’m not sure if this is correct.
Just to refresh your memory if you don’t wanna go back in this thread, I have a 1993 OMC cobra 5.8 L. I do not have or can open your images of the wiring diagram for ESA , interrupter, over stroke switches. I need clarification on the switches being normally open or normally closed. Both micro switches are labeled NO with wires on C and NO TERMINALS.
To clarify the interrupter switch with roller in V the ohm meter is at infinity. When roller is at top of interrupter the meter is zero or continuity is achieved. Is this as you expect?
The overstroke switch in neutral is at zero or continuity. When the over stroke switch is in forward or reverse there is no continuity it’s opened or at infinity. Is this as you expect?
All is working for shift but going from in gear to neutral requires a pause and jiggle before it will disengage gear. Is this as expected.
Lower drive has been disassembled and rebuilt. All cables have been replaced. The wiring is original as I’ve had the boat since new but never been totally happy with the shifting. Is the original wiring incorrect?
Thanks Bob

Lou, Good evening— can you tell me if you received the above post? We talked last in 2022. Above is a follow up on new work you recommended.

 

[Lou C]

The interrupt switch is normally open and the overstroke switch is normally closed.
This is from my OMC shop manual:
for the interrupt:
After disconnecting the plug for the ESA behind the shift cable bracket. insert the test probes into the male connector plug (blue leads). Ohmmeter should be set on the high ohms scale. With the control system in neutral, the ohmeter should show infinity.
Manually lower and raise the load lever, this will trigger the level on the interrupt switch. The meter must show a zero reading when held in either direction. Replace the switch if it fails to show zero under this test.
For the overstroke:
now for this you are moving your ohmmeter probes to the cavity with the black leads....
with the control in neutral, the meter must show a zero reading.
manually depress the overstroke switch stud, the meter must show infinity. Replace the overstroke switch if this is not the case.
If you don't have an OMC shop manual for your model and you're going to have this boat for a while, I think it's going to be very helpful to have one! I use mine all the time.

 

[Rhc]

---

The interrupt switch is normally open and the overstroke switch is normally closed.
This is from my OMC shop manual:
for the interrupt:
After disconnecting the plug for the ESA behind the shift cable bracket. insert the test probes into the male connector plug (blue leads). Ohmmeter should be set on the high ohms scale. With the control system in neutral, the ohmeter should show infinity.
Manually lower and raise the load lever, this will trigger the level on the interrupt switch. The meter must show a zero reading when held in either direction. Replace the switch if it fails to show zero under this test.
For the overstroke:
now for this you are moving your ohmmeter probes to the cavity with the black leads....
with the control in neutral, the meter must show a zero reading.
manually depress the overstroke switch stud, the meter must show infinity. Replace the overstroke switch if this is not the case.
If you don't have an OMC shop manual for your model and you're going to have this boat for a while, I think it's going to be very helpful to have one! I use mine all the time.

So glad to see you are on line and thanks for your input once again. Yes I do have a OMC manual but it’s for the MED & MEF (4 bbl ?). I’d like to update to my boat motor which is 58FAPRJVN. This is Mar 1993 with EFI 5.8 and ESA. Do you know the OMC manual that is exactly for this motor and drive. Thanks.
So I read your info from your manual - it agrees with mine. My question is why is the over stroke switch labelled as normally closed while the wiring on my switch is inserted into C and NO. The major difference I see is that my switch has a control arm, (similar to interrupter switch ) not a button. When your manual says push the button, I would have to lift the lever arm - for continuity which is neutral or closed position.
Our info agrees but — my label and wire connections (see above) shows wires in C-NO positions. I would take this to be a normally open switch? Perhaps mine is a mislabelled switch? Both our written function info seem to agree. Eg — closed in neutral and open in Fw & Rev. Sorry for the excercise. Is this just a lot of words and maybe relates to some labelling issue?? Or configuration of lift arm versus push button?
Thank you.

 

[Lou C]

There is a lot of confusion over what OMC did in certain years, and a lot of the documentation is hard to find because they have been out of business for so long. So what I'd do is post up a pic of what you have, I thought they eliminated the overstroke switch on the later models and used an ESA with a timer instead. In fact if you buy an OEM ESA for my model for instance, that's what they will sell you. The original style one that was for my model has been discontinued and replaced with the "updated" one that does not use the overstroke switch.
Now if you want the original style ESA module (that still uses the overstroke switch) if yours isn't lowering the RPM as it should, CDI Electronics sells them, I have one of theirs on my Cobra and it works just like the factory set up.
Just to make sure what you have is working right, run the engine in neutral on the water hose, trigger the interrupter, and see that it lowers the RPM from about 600 to about 450, that means that it's working. If not you have to figure out why, it could be the switch or the ESA module. Remember that you have to trigger that interrupter by hand, shifting the drive on land will not trigger it because there is not enough load on the prop to put a load on the shift cable when you try to shift to neutral. That only happens with the load of the water against the prop. When I shift mine to neutral in the water, you can see the tach needle dip for a split second, that's the interrupter doing its thing and the drive goes right into neutral like it should.
Now shift the outdrive into gear, and trigger the interrupter, and see if it still drops the RPM, it should not because the overstroke switch is supposed to cancel the interrupter when the drive is in gear. If it works like that, then this part of your shift system is working like it should. If all this works and you still have stiff shifting going from in-gear to neutral, your cables could be worn (but not likely if you replaced them not so long ago) your bellcrank in the pivot housing could be crudded up with water deposits, because that gasket can leak between the drive and the pivot housing. I grease that area with OMC triple guard every time I pull the drive. The other possibility is your remote control could be worn out, with some lost motion, perhaps the cables while still good, aren't moving evenly in both directions.
Just out of curiosity what is your idle RPM? It shouldn't be more than 600 with the boat in the water. If it is higher like 900-1000 the ESA system can't lower the idle rpm enough to let the drive shift into neutral. Sometimes you can have a problem with the idle drifting up, due to slack in the accelerator cable, this can be adjusted out as per the manual. I also had this issue with mine and if the idle drifted up to like 760--800 I could feel the difference right away, it would still go into neutral, but it took a bit more force on the remote control, with it at 600 it takes like one finger to push it into neutral. That's how a properly adjusted Cobra is supposed to be lol.

 

[Rhc]

There is a lot of confusion over what OMC did in certain years, and a lot of the documentation is hard to find because they have been out of business for so long. So what I'd do is post up a pic of what you have, I thought they eliminated the overstroke switch on the later models and used an ESA with a timer instead. In fact if you buy an OEM ESA for my model for instance, that's what they will sell you. The original style one that was for my model has been discontinued and replaced with the "updated" one that does not use the overstroke switch.
Now if you want the original style ESA module (that still uses the overstroke switch) if yours isn't lowering the RPM as it should, CDI Electronics sells them, I have one of theirs on my Cobra and it works just like the factory set up.
Just to make sure what you have is working right, run the engine in neutral on the water hose, trigger the interrupter, and see that it lowers the RPM from about 600 to about 450, that means that it's working. If not you have to figure out why, it could be the switch or the ESA module. Remember that you have to trigger that interrupter by hand, shifting the drive on land will not trigger it because there is not enough load on the prop to put a load on the shift cable when you try to shift to neutral. That only happens with the load of the water against the prop. When I shift mine to neutral in the water, you can see the tach needle dip for a split second, that's the interrupter doing its thing and the drive goes right into neutral like it should.
Now shift the outdrive into gear, and trigger the interrupter, and see if it still drops the RPM, it should not because the overstroke switch is supposed to cancel the interrupter when the drive is in gear. If it works like that, then this part of your shift system is working like it should. If all this works and you still have stiff shifting going from in-gear to neutral, your cables could be worn (but not likely if you replaced them not so long ago) your bellcrank in the pivot housing could be crudded up with water deposits, because that gasket can leak between the drive and the pivot housing. I grease that area with OMC triple guard every time I pull the drive. The other possibility is your remote control could be worn out, with some lost motion, perhaps the cables while still good, aren't moving evenly in both directions.
Just out of curiosity what is your idle RPM? It shouldn't be more than 600 with the boat in the water. If it is higher like 900-1000 the ESA system can't lower the idle rpm enough to let the drive shift into neutral. Sometimes you can have a problem with the idle drifting up, due to slack in the accelerator cable, this can be adjusted out as per the manual. I also had this issue with mine and if the idle drifted up to like 760--800 I could feel the difference right away, it would still go into neutral, but it took a bit more force on the remote control, with it at 600 it takes like one finger to push it into neutral. That's how a properly adjusted Cobra is supposed to be lol.

Thanks for your detailed explanations. I will complete the test as you’ve suggested. At this point, I would be suspicious of the remote control device as it is original. My RPM is about 625 maybe 650. It does shift but I think it could be easier. Will report back thank you.

 

[Rhc]

View attachment IMG_4288.jpeg

 

[Lou C]

https://www.marineengine.com/parts/omc-parts/omc-boat-parts.php?year=1993&hp=5.8&model=58FAPRJVN&manufacturer=OMC+stern+drive&section=Shift+Bracket

I looked up what you have and it is as you described, you have 2 switches with the lever arm on them vs the one with the lever arm and the other that just has the button on the earlier models. Not having seen a shop manual for yours, I'm going to guess it works the same way but uses the load lever to trigger both instead of 2 different methods as on the older models like mine.
Scott Danforth used to have a link to the original factory manuals, see if you can find out if they are still out there....you can also check ebay, they do show up there sometimes....

 

[Lou C]

View attachment 401768

doesn't look too high, when you trigger the interrupt switch, does it drop the RPM in neutral to about 450?

 

[Rhc]

doesn't look too high, when you trigger the interrupt switch, does it drop the RPM in neutral to about 450?

Yes

 

[Rhc]

Yes

Do you know of a remote shifter that would have wires and fit to suit my 175496 30 JR

 

[Rhc]

Do you know of a remote shifter that would have wires and fit to suit my 175496 30 JR

 

[Rhc]

 

[Rhc]

View attachment IMG_4304.jpeg