OMC 5.7 acceleration problem - pics included

Crapduster

Seaman Apprentice
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Jan 26, 2008
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40
Re: OMC 5.7 acceleration problem - pics included

Ok, I went up there and put my hands on it. I actually have the original cobra owners manual that came with the boat in 1990. The part that looks like it is pulled apart and not plugged in all the way is called an "electrical cable connector" -straight from the manual.

It is definitely not intended to be pushed together, although it very much looks like it. The picture in the owners operators manual backs this up.

I will see if I can take a decent picture of the owners manual picture I have. Don't have a scanner to scan it in. I do have one at work though... I will see about scanning that one page and posting it.
 

Maclin

Admiral
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May 27, 2007
Messages
6,761
Re: OMC 5.7 acceleration problem - pics included

I would take the connectors apart and look for corrosion on the actual connector pins. I would then unplug and plug it back in several times to get the surfaces all electrically new again, similar to re-seating a card in your world;). I am not sure if this has any bearing on the problems you face now but I would do this anyway. At the same time I would see if I could get the connector all the way together to seal the connection.

The rubber housings certainly look like they are designed to meet and seal out the elements and protect the connector pins. Perhaps the pic in the manual shows them slightly apart just for clarity. A black and white pic of them all pushed together may have read like a one piece tube.
 

Crapduster

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Jan 26, 2008
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Re: OMC 5.7 acceleration problem - pics included

Ok, I took a picture of the picture in the original OMC operators manual I have. Look at my pics at the top of this post, then look at the pic from the manual in the link below (it is bigger than 640x480 for detail sake, so I posted the link). It looks to me like there is some type of rubber "sleeve" held on with a clamp, around what is the exposed metal connectors in my pictures. I googled for some 350/5.7 OMC engines and saw the same thing as in the manual... what looks to be a "sleeve" held on with a clamp.

http://i104.photobucket.com/albums/m172/themot/photo.jpg


I want to elaborate some on how closely I looked at this connector last night. For 20 minutes solid I tinkered only with it. It was dark when I went to the storage facility, so I wore my headband LED fishing light. When I say I was close, I was standing in the engine compartment with my eyes no more than 8" and looking a 45 degree angle toward the connectors looking for damage. I expected to find some markings on the metal, or some very small stress cracks, damage around the rubber where the connectors leave each side of the rubber (the steel rods look like connectors, but are in fact solid rods with no breaks or "connects" in them... I mean they run out one side of the connector right into the other side) Just for grins I tried to "squeeze" it back together and no bueno... I put enough force to it that I thought it might break.

Someone back me up or tell me i'm crazy here :)
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,524
Re: OMC 5.7 acceleration problem - pics included

You are going to need to pull it apart and clean the connections. I suggest disconnecting the battery before you do this.
 

triman

Petty Officer 2nd Class
Joined
Sep 30, 2002
Messages
124
Re: OMC 5.7 acceleration problem - pics included

Looking at the supplied photo and the manual photo, the electrical connector should be closed tighter. In the photo from the manual the connector support is to the extreme left of the connector - in the supplied photo the clamp is inboard of the last ridge. If that clamp was at the extreme end the connector would be closed up.
 

Maclin

Admiral
Joined
May 27, 2007
Messages
6,761
Re: OMC 5.7 acceleration problem - pics included

Ok, I took a picture of the picture in the original OMC operators manual I have. Look at my pics at the top of this post, then look at the pic from the manual in the link below (it is bigger than 640x480 for detail sake, so I posted the link). It looks to me like there is some type of rubber "sleeve" held on with a clamp, around what is the exposed metal connectors in my pictures. I googled for some 350/5.7 OMC engines and saw the same thing as in the manual... what looks to be a "sleeve" held on with a clamp.

http://i104.photobucket.com/albums/m172/themot/photo.jpg


I want to elaborate some on how closely I looked at this connector last night. For 20 minutes solid I tinkered only with it. It was dark when I went to the storage facility, so I wore my headband LED fishing light. When I say I was close, I was standing in the engine compartment with my eyes no more than 8" and looking a 45 degree angle toward the connectors looking for damage. I expected to find some markings on the metal, or some very small stress cracks, damage around the rubber where the connectors leave each side of the rubber (the steel rods look like connectors, but are in fact solid rods with no breaks or "connects" in them... I mean they run out one side of the connector right into the other side) Just for grins I tried to "squeeze" it back together and no bueno... I put enough force to it that I thought it might break.

Someone back me up or tell me i'm crazy here :)

Okay, I'm goin' in.......CrapDuster, dude, YOU ARE CRAZY. The pic from the manual shows a FULLY CLOSED connector with a clamp around the joint.....:confused:
 

Crapduster

Seaman Apprentice
Joined
Jan 26, 2008
Messages
40
Re: OMC 5.7 acceleration problem - pics included

I'll go back up there after work or possibly on lunch break and have another go at the electrical connector.

I have to agree with everyone that exposed connections uhhhh, just don't seem right. Goes against everything I know too.

I am not going to let stubborness stand in the way of good advice on this one. I will report back later today after I check it out again. At least it will be daylight when I look at it this time. :)

I am going to put the camera in macro mode and take some super closeups if I can't figure out a way to get this thing back together.

The other thing that kinda makes me believe y'all are right about the connector is that the engine has been replaced twice in the boat; it is very possible that the cable harness from one end or the other got pulled to tight or caught on something while engine was being pulled. Lots of possibilities.

Thanks!

Tom
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,524
Re: OMC 5.7 acceleration problem - pics included

PULL THE CONNECTOR APART...

...then clean and reinstall! :)

This may not be the source of your original problem but it is obviously very wrong and is easy to fix.
 

bipp

Cadet
Joined
Jun 11, 2002
Messages
25
Re: OMC 5.7 acceleration problem - pics included

You need to look at my picture.
 

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Crapduster

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Re: OMC 5.7 acceleration problem - pics included

Bipp, you're spot on. But here is what I am running into (comments in next paragraph). Y'all must think I am hopeless by now, but I swear I am not holding back. I am reporting how it is whether I am right or wrong.

Here are some pictures from tonight. Just links, photos are too big for here but reducing size will reduce the detail too much.

http://i104.photobucket.com/albums/m172/themot/P1000963.jpg

http://i104.photobucket.com/albums/m172/themot/P1000959.jpg

Ok, it was dark when I got up there cause of dang work. I pulled and twisted till it come apart. The pins are longer than the holes are deep; I think... didn't have a measuring apparatus with me but looks to be that way. This normally wouldn't make sense (maybe it still don't?) but it has had two engine replacements since 1990. The last one in 2005 with 75 hours on the motor now. Going out on a limb, but newer wiring harness on the motor side? I stared at this dumb thing for awhile and looked at how deep the female (motor) side of the connector appeared versus how long the male side was. It will probably be Saturday before I can spend some daytime hours looking at this. I work 10a-7p. I want to re-focus on some other problems though if y'all are ok with that?. The connector is but one problem and I will get that fixed. I have a dremel with a cutting blade, I can cut the connecting male prongs to the right length to properly fit the connection together if that's what it takes. I do agree that it should be all the way together.

Let me add some info that screwed up on from my very first post and see if this changes anything. After looking at what I thought was a fuel filter and water separator, it turns out to be a fuel filter only. I don't know how old it is, but appears to be fairly new and there was an extra new "Wix" fuel filter with the boat. The 60 gal tank was completely empty while the boat sat for 5 months waiting to be sold. This is in Houston, TX; We have 10% ethanol gas and high humidity. I will be getting a quality fuel/water separator in place of the fuel filter this weekend. When I put 1/2 a tank in for the first test run, I put premium from a local Shell and immediately added the marine sta-bil (the green stuff) to the gas.

The carb, the original 1990, has been through two motor swaps, the last motor swap was in 2005 and the carb's last rebuild was in 2002, I would like to think it was taken care of in the shop during the motor swaps, but who knows? I don't know how many times it sat or how long between the rebuild in 2002 and now. It had two different owners between 2002 and August 2009 when I bought it.

The boat mostly idles just fine. It stays idling, albeit a little high at times making it tough to shift. From what I gather and what I have read, a lot of OMC problems start with the carb. It doesn't seem to have any problems at low rpm's; if I baby the throttle a little at a time, I can consistently get the boat on plane after plowing water and get it up to 48MPH with 30gal fuel and me and a 4800lb Chris Craft 225 Limited. The motor makes no weird noises other than a little laboring and spitting when trying to get it out of the hole, it just doesn't have the power band that should be there. There is not a whisp of smoke from the motor under any condition.

I am going to get the engine electrical plug fixed, get a fuel filter/water separator installed and get a new or rebuilt carb on there and test in the next week or two. Unfortunately for me, testing means dragging the boat down to the marina by myself, which is a can do only on the weekends deal. I will also do the ESA tests that need to be done to make sure that thing is working as designed.

Thanks. Tom
 

bruceb58

Supreme Mariner
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Mar 5, 2006
Messages
30,524
Re: OMC 5.7 acceleration problem - pics included

You shouldn't have to cut the connectors down, they should already be the proper depth.

The spin on filter that comes with the engine is already a water seperating filter. You should definitely change it. Dump its contents into a clear glass jat and see if water or other junk settles to the bottom.

Sounds like your engine is running lean when you accelerate. Check that the carb's accelerator pump is working. You should be able see squirts of gas when you open the throttle. Check for this with the engine not running. Very possible you will need a carb rebuild if you are running lean.
 

JustJason

Vice Admiral
Joined
Aug 27, 2007
Messages
5,319
Re: OMC 5.7 acceleration problem - pics included

Stick a nail or a pin down 1 of the female sides of the connectors, mark it, and then compare it with the male side to see if its a fit or not. Then stick the pin down every hole on the female side to make sure you don't have any junk thats preventing the connecter from seating.

(good catch on the connecter in your earlier posts BruceB)
 

Maclin

Admiral
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May 27, 2007
Messages
6,761
Re: OMC 5.7 acceleration problem - pics included

The female plug may have a busted pin down in it, never know what you will find on a previously owned anything.

My "you are crazy" comment, hope you took it the right way, just trying to answer in the vernacular requested..:D

There are tools to push the pins out if it comes to that. But as with anything they are designed to work well when everything is new. You do have a bit of a challenge ahead on that connection I think.
 

Crapduster

Seaman Apprentice
Joined
Jan 26, 2008
Messages
40
Re: OMC 5.7 acceleration problem - pics included

Maclin, I appreciate all your comments. Sometimes a sanity check is needed and you provided that. I probably would not have taken another look at that connector without all the urging.

I will check for a broken pin in there. I didn't even think about that possibility.

Thanks for everyone who has helped. This thread will get much more exciting once I can get some time and parts to start working on it and then test and post results. I have plenty of patience, so this thread may be on-going for a month or two.

Primary goal is get boat running strong for next season... this season is close to over and I will be back in my fishing boat before long :)

Tom
 

dolphin1

Cadet
Joined
Jul 19, 2007
Messages
20
Re: OMC 5.7 acceleration problem - pics included

somebody has cut the extended portion of the male end of the connector off, thats why it looks like it isn't in all the way even though it is.
 

JustJason

Vice Admiral
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Re: OMC 5.7 acceleration problem - pics included

Good catch dolphin1... in looking at the bigger pictures, it looks like your right.
 

Maclin

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May 27, 2007
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6,761
Re: OMC 5.7 acceleration problem - pics included

That is a thought I had as well, that something was missing, like a sleeve or extension of the rubber part on one of them, good eye!

If the connector bottoms out and is still not covered then I would probably opt for some non stick rubber tape wrap with clamps on each end at this point.
 

Crapduster

Seaman Apprentice
Joined
Jan 26, 2008
Messages
40
Re: OMC 5.7 acceleration problem - pics included

somebody has cut the extended portion of the male end of the connector off, thats why it looks like it isn't in all the way even though it is.

Gentlemen, sorry I have been away for a month. About a week after my last post, I got a nice case of Vertigo caused by a viral infection in the inner ear. I have never ever felt like that in my life! Not even close! That is a terrible feeling and the effects last for weeks. So I am just getting back to projects now.

Dolphin1 is dead-on. I was up there playing with that connection today and I knew without a doubt that all holes were equal depth (nothing broken off in them) and that the pins were in as far as they were going to go. That is when it dawned on me why the edges were crooked ... they were sliced off with a knife. Here are some more pics to back up what Dolphin1 said. Notice how the connection now rests in that wire retainer the same way it is pictured in the OMC manual pictures. Some good quality electric tape will take care of that gap. I used some electric grease in there before I put it back together.

I discovered something else today. Today was the first time I took off the distributor cap and lo and behold a Pertronix Ignitor was installed. One thought comes to mind. The Pertronix are supposed to not work so well with the OMC ESA module without a little diode workaround. I have the .pdf that shows the diagram and part numbers for the workaround. It is simple enough to buy and make from Radioshack. I looked for something like this to be wired in and couldn't find anything. I looked pretty good, and there are only so many places it could hide around the distributor area. So I am thinking that when the Pertronix was installed, that the workaround to the ESA problem was never put in place or perhaps a 3rd party ESA was used, but I doubt it. I definitely have hard-to-shift issues. I have read that there are 3rd party ESA's that can be used that do not have the shift problem and you do not have to use a diode work-around either.

A week from now I am ordering a rebuilt Qjet carb and a new Holley marine fuel pump and routing all fuel lines correctly for safety. Currently, there are some things not in place (how I bought it) that should be there for safety. The electric fuel pump is automotive and from god-knows-what... I want the return line from the carb to the pump in place, so I need to get a marine pump; those Holleys look awesome.

Two-three weeks from now I should have a new-rebuilt Qjet installed, new plugs, new water separating fuel filter, new marine Holley fuel pump and the diode fix for the Pertronix.

I know many of you might ask why would I throw money at it like that, but it's not out of *complete* ignorance... only partial :) I already have a two stroke motor that I do most of the work on, rebuild carbs, etc... I put a lot of maintenance hours into that thing. In this case, I would rather not learn to rebuild the carb on this motor yet, I want to start with a baseline that I know has been professionally rebuilt and tested. At minimum, I know that the parts that wear out are new and that the carb has been cleaned. The new fuel pump I need simply for the safety factor if nothing else. It has the return port for a hose from the carb.

I would be very surprised, if after replacing these things and adjusting idle, that I would have any more problems. I do not like having mechanical problems. I like my stuff to work unless it is just that time for something to let go... but not because of bad maintenance. I am still in the mode of un-doing prior owners mistakes and misdiagnosis'.

What'chall think about the Pertronix installed and not having the diode workaround for the ESA in place? This seems to only be a problem with OMC from what I have read.

photo-1.jpg


photo-2.jpg
 

Crapduster

Seaman Apprentice
Joined
Jan 26, 2008
Messages
40
Re: OMC 5.7 acceleration problem - pics included

Just a quick update, no new news on sorting the problems out, but that is coming soon. Glad I live in the south and can work on this through fall and winter. :) I am a slow-poke. Just wanted to share a pic of some new components that came in today. I don't have to tell y'all what those are. The newly rebuilt carb will be here tomorrow (Friday) and with some luck I will get everything put together for a test run on Sunday. Also, I figured out how to post thumbnails instead of large pictures... I know some folks will appreciate that! If these three things plus some new plugs gapped properly doesn't solve the problem then I have to bite the bullet and get a quality electrical tester and start checking voltages.

 

Alpheus

Lieutenant Commander
Joined
Aug 3, 2009
Messages
1,759
Re: OMC 5.7 acceleration problem - pics included

Want to sell your old carb?
 
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