229 v6 OMC - Loses power once warmed up (lean???)

Joined
Apr 21, 2003
Messages
18
Hi, I have an 82 Renken with the Chevy 229 v6. It has points(which are probably the source of all my problems) and a rochester 2 bbl carb. Here is what has been happening. The first time out on the boat, I ran it for around an hour to an hour and a half. Then, it started losing power. It slowed itself down, and the motor sounded bogged down. Then it started pinging and backfired, which cut it off. The temp had risen too. I had to crank it back up because I was in traffic and at idle, the temp went right back down. When I gave it gas, it just sounded bad, but didnt actually accelerate. It seemed like a fuel delivery problem. I changed the fuel water separater(twice now) and rebuilt the carb. Took it out twice since then and the same thing keeps happening, but quicker each time. It only took 45 minutes, then not even 20 the last time. I changed the coil this weekend and it sounds better, but I have to get it on the water to get it to do it. It will run when it is doing this, but not hard. It will not go on plane although the temps dont seem to rise as much, but that may be because I am not holding the throttle open since something is clearly wrong. I set the points to .18 and the timing to 10 degrees, like it says in the book. It was at 8 degrees, but that would make it knock more, not less, now that I have set it to factory spec. I used a marine carb rebuild kit and set the float. The other odd thing is that at idle, in the yard, you can hear an occasional miss and giving it gas, sometimes it will just stumble and miss real bad, but other times it just revs up like it should. I was thinking of changing the fuel pump, would and automotive style be acceptable? Also, before I bought it, the man had his mechanic put the points in and they are from the car parts bin. Could that be part of the problem? It was doing this with the previous owner too, but he thought changing the points, wires, cap and rotor had solved the problem.
 
Joined
Apr 21, 2003
Messages
18
Re: 229 v6 OMC - Loses power once warmed up (lean???)

edit- points at .018, not .18. You guys thought you had solved my problem huh!
 
Joined
Apr 21, 2003
Messages
18
Re: 229 v6 OMC - Loses power once warmed up (lean???)

Also, my boat parts supplier said he could get an electronic ignition kit for the boat for like 70 bucks. I thought that sounded like a very good idea, because I have always had problems with points. Do you guys think that could be the source of my problems anyway?
 

tmclendon

Seaman
Joined
Mar 31, 2003
Messages
74
Re: 229 v6 OMC - Loses power once warmed up (lean???)

Sounds like plain old overheating to me, rather than an ignition problem. If you lose cooling, the head will heat up (red hot+) and cause detonation. Are your sure the water pump in the lower unit is good? Take a look at the ball joint at idle, there should be a good spray of water in that area. Beware, it's easy to crack the head or block if this is the problem!<br /><br />The electronic ignition is good (petronix I presume?) but be aware that you will have to put in a modification to retain the function of the ESM (Electronic shift module, which drops the RPM when you shift). Points are easy to blame, but if they have been working for 22 years, they must be doing OK. <br /><br />Good luck!<br />Tom
 

tmclendon

Seaman
Joined
Mar 31, 2003
Messages
74
Re: 229 v6 OMC - Loses power once warmed up (lean???)

PS Don't use an auto fuel pump. The marine units are a bit different (they have that goofy vacuum tube up to the carb so you can tell when the diaphram ruptures). <br /><br />Tom
 
Joined
Apr 21, 2003
Messages
18
Re: 229 v6 OMC - Loses power once warmed up (lean???)

Well, I had been thinking that it wasnt cooling related, but I cant really tell you if what the water is doing is right or not because it had this problem when I bought it, so I have not noticed any change anyways. Still, I bet it hasnt been changed in the last 8 years anyway, so I better check it out.
 

akriverrat

Chief Petty Officer
Joined
Oct 31, 2002
Messages
588
Re: 229 v6 OMC - Loses power once warmed up (lean???)

sounds like rust restricted risers. take em off and have a look. 8 years is old for raw water cooled manifolds and risers.
 
Joined
Apr 21, 2003
Messages
18
Re: 229 v6 OMC - Loses power once warmed up (lean???)

Yeh, maybe you guys are right. I will take the risers and possible the manifolds off this weekend and see what I can find out. When you pull them off, is there any gaskets between the manifold and risers? Also, on the manifold to head, what kind of header gaskets do I use?
 

akriverrat

Chief Petty Officer
Joined
Oct 31, 2002
Messages
588
Re: 229 v6 OMC - Loses power once warmed up (lean???)

you can get what you need by clicking on marine mega mall at top. then do search 'gaskets'.
 
Joined
Apr 21, 2003
Messages
18
Re: 229 v6 OMC - Loses power once warmed up (lean???)

Well, part of the problem was a bad plug wire and the carb rebuild kit I used had the wrong specs for the float height. Use the ones in the OMC service manual instead. (as per my mechanics advice) I will reset the float and tell you guys if it helped. I checked out the cooling system, it hasnt acutally been that long since it was serviced and it was ok. I also checked the cam timing chain, it is set correctly.
 
Joined
Apr 21, 2003
Messages
18
Re: 229 v6 OMC - Loses power once warmed up (lean???)

Well, we are back to the start now. I have the float height set as per the OMC service manual (1/2 inch, with 1 3/4 drop) and new points, condensor, and ignition coil. I took it out and once the choke cut off (warmed up) it started knocking. Well, I went and bought a new fuel pump. I should have it all back together today, so I sure hope this is the problem.
 
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