2.3L omc swap to 4.3L merc project.

[Speak]

Hi guys, I have acquired a complete boat with a 4.3L merc (2bbl 12 bolt intake) with an Alpha one that I plan on swapping into my 1989 Bayliner capri 1750. I like my boat and enjoy wrenching on it. I have already done the stringers and transom and interior so the boat it solid. I have always wanted to put a 4.3 in it so here goes.
The motor serial is 0C525578 and the drive is 0C684021. I believe the engine and drive are late 80's but not sure. I got the engine running. compression is 125 psi. Battery was low so I think the numbers could come up with a fresh charge. The drive fluid is clean with no water in it. I will pressure check it later.

My question are this. How much play is allowed if any in the shift shaft rod, the part that connects to the bellcrank on the bellhousing? Mine has some side to side movement. Is this supposed to be tight?

The ujoints are rusty, and the gimbal bearing is seized. Should I replace the drive shaft seal along with the ujoints? The seal does not appear to be leaking but the job to do the ujoints is big and seams to be silly not too.

Should I be concerned with preload if do the seal? Can I just reassemble? I do have the service manual from the sticky, but Im a bit nervous about diving into that. Any input on this would be great.

Thanks Stu

 

[gm280]

Obviously nobody can tell you what to do without knowing your abilities to do such things. If you have a good working ability with tools and such things, then go for it and things will work out as you learn along the way. However, if you don't think you have such abilities, then have someone else do the work. But then it will cost a LOT and you won't learn anything... Just my $0.02 cents...but worth a whole lot less...

 

[Speak]

Obviously nobody can tell you what to do without knowing your abilities to do such things. If you have a good working ability with tools and such things, then go for it and things will work out as you learn along the way. However, if you don't think you have such abilities, then have someone else do the work. But then it will cost a LOT and you won't learn anything... Just my $0.02 cents...but worth a whole lot less...

Thanks gm280. I'm a lic auto tech so no problem. Just nervous because it's new to me. Any thoughts on the shift shaft play?

 

[Rick Stephens]

As long as the seal is good, a bit of play is not an issue. Too much play and the seal will leak water into the shift cable linkage area of the bell housing.

Not hard to install the updated bushings and seals.
http://www.iboats.com/Bell-Housing-...7894703--session_id.735244115--view_id.172463

Rick

 

[Rick Stephens]

The ujoints are rusty, and the gimbal bearing is seized. Should I replace the drive shaft seal along with the ujoints? The seal does not appear to be leaking but the job to do the ujoints is big and seams to be silly not too.

Thanks Stu

No way would I just replace the drive shaft seal just cause I am working on the ujoints. That's a new to you used sterndrive. You need to pressure test it to know if any of the seals leak anywhere before choosing what to reseal.

Rick

 

[Speak]

No way would I just replace the drive shaft seal just cause I am working on the ujoints. That's a new to you used sterndrive. You need to pressure test it to know if any of the seals leak anywhere before choosing what to reseal.

Rick

Good point Rick. I should know better. Drained the fluid last night and it came out nice and green. No water.
Question Rick. When I remove the drive shaft from the drive, what seal seals the two together? Meaning what seals the drive shaft to the drive case. I don't understand this by looking at the manual.
Cheers

 

[Rick Stephens]

You don't have to pull anything apart to change the ujoints except pull the leg off. I'd probably split the upper off and set it on the bench and start pressing the ujoints out. The seal for the driveshaft going into the upper housing is behind the big nut. Need that big spanner wrench to get that off and then disassemble the bearings to get to that seal. No reason to do that unless you show pressure loss there.

Rick

 

[Speak]

You don't have to pull anything apart to change the ujoints except pull the leg off. I'd probably split the upper off and set it on the bench and start pressing the ujoints out. The seal for the driveshaft going into the upper housing is behind the big nut. Need that big spanner wrench to get that off and then disassemble the bearings to get to that seal. No reason to do that unless you show pressure loss there.

Rick

Rick that big nut blocks the movement of the bearing cups. No way for me to press them off as they will hit the big nut.
Stu

 

[Speak]

Rick here is the play Im talking about in the shift shaft...... Too much? or ok in your opinion.

 

[Rick Stephens]

THAT ONE. Oh. No problem. That's the shift shoe and it just sits on top of the lower shift shaft. S'posed to be loose, just like that.

It's a tight fit, but it would be better to round off a corner of one of the teeth than try and pull the whole thing apart to replace the ujoints. They'll come out.

Rick

 

[Speak]

THAT ONE. Oh. No problem. That's the shift shoe and it just sits on top of the lower shift shaft. S'posed to be loose, just like that.

It's a tight fit, but it would be better to round off a corner of one of the teeth than try and pull the whole thing apart to replace the ujoints. They'll come out.

Rick

Ok glad to hear about both those things. I will make a pressure tester this week end and report back my findings. If holds pressure then I will put just joints in it and an impeller.

 

[Speak]

Had time today to pull the engine from the donor boat today

Pressure tested the drive as well held 10psi for several hours

 

[Speak]

Tried to post pictures from my phone it's the worst keep getting errors

 

[Speak]

I have determined that the coupler on the donor 4.3l is pooched as the splines are worn and sharp looking. My drive shaft is the one with 2 orings. The only coupler I find is 18-2175 which includes a drive yolk. Is this my only option? My current shaft is ok. Do I have to update my driveshaft ?

 

[Speak]

Hello again. Still working on this project, evaluating whats what and putting together a list of whats really needed. Couple questions. I did pressure check the drive and it held 5 psi for afternoon with no sign of it dropping, the oil was clean with no water. However when I split the drive I noticed that the shaft that connects the two halves has a grove worn in it from the seals. Is this normal, or a death sentence? Also the lower bearing carrier has a lot of corrosion on it, especially around the end, is this also an issue?

 

[Speak]

Additionally when looking inside the upper I noticed what looks like a lot of corrosion. Especially around or over the oil passage way. Is this also bad, and if so is there a solution.

 

[Faztbullet]

I have seen worse and a little clean up and zinc chromate paint and you should be good to go on drive. You will need to reglass the transom as the mercruiser and cobra will not line up, or order a kit from SEI and use the cobra gimbal housing and trim...

 

[Bondo]

The only coupler I find is 18-2175 which includes a drive yolk. Is this my only option?

Ayuh,.... Where ya shoppin',..?? iboats should list the coupler, 'n shaft Alone, as well as a set,....
No need to change the shaft if it's still Good,....

You will need to reglass the transom as the mercruiser and cobra will not line up,

I agree with Faztbullet, that the housin's are fine,....

I Disagree 'bout the transom cut-out, 'n holes,....
I'm pretty sure both Volvo, 'n OMC used the Merc keyhole for the Cobra series,....

 

[Speak]

Ayuh,.... Where ya shoppin',..?? iboats should list the coupler, 'n shaft Alone, as well as a set,....
No need to change the shaft if it's still Good,....



I agree with Faztbullet, that the housin's are fine,....

I Disagree 'bout the transom cut-out, 'n holes,....
I'm pretty sure both Volvo, 'n OMC used the Merc keyhole for the Cobra series,....

Thanks Bondo - yup you are right the key hole is bang on and matches up. I am shopping at a local marine supply store. I have not priced out the coupler out yet here but it looks like its going to be over $200 easy. Expensive sucker.

 

[Speak]

Would you guys res use these manifolds? I am concerned that they are too rusty inside. When I took them off the motor, and turned them upside down a tone of rust debris came out. This engine must have been sitting for a few years. I did soak the insides with WD-40 in an effort to try preserve whats left. I am just worried that things might be thin inside. There is no evidence of water leaking in the exhaust (I did have it running last year)