Volvo Penta 4.3GL problems I'm Confused??

[enforcer30]

Hi again guys, Still not cured. 96 Volvo 4.3GL runs great accept it will not pull more than 4,000 RPM's after a overheat. The prop and skeg are ok, Compression is 175-180 all six holes, New cap rotor plugs wires and module, Used a external fuel tank and fuel pump to varify check ball anti siphon and it's fuel pump (no change), New fuel water sep., New Carb (it's opening all the way), Pulled the exhaust and found a flap down by the lower unit repaired it and removed the other one (no change), I varified the tach is correct +/- 50, I have played with the base timing (no better than 4K).
What gives, what am I missing????? There is no miss no hesitation it planes alright a little week just will not pull all the way. In neutral I did hit 5K just for a moment. I wasn't about to let it rev there.
Anyone have any more ideas. At this point I would listen to anybody or thing. I appreciate all the help and ideas I got on my last post. Thanks to all.

Once again Thank You, Barry

 

[Don S]

Re: Volvo Penta 4.3GL problems I'm Confused??

You could pull 5000 rpm in neutral if you took half the plug wires off. So that's a non test.
Have you verified that you are actually getting full advance on the distributor?

 

[enforcer30]

Re: Volvo Penta 4.3GL problems I'm Confused??

Well I ran the engine to right around 2K I can't remember the exact RPM, but I was showing 22 deg. (no shunt) at 600 RPM I was at 11 deg. (no shunt). So I can only assume it is advancing.

Dosn't the module advance it? If so I have tried 2.

Thank you for the responce. If I am wrong or if there is another way to check it let me know thanks again.

 

[superpop]

Re: Volvo Penta 4.3GL problems I'm Confused??

Do you have a shunt, sounds like it is not timed right. The module doesn't matter if the timing is off. I have the same motor and the timing is very particular. Also, are you sure the secondaries are opening. Not sure if you have the 2 or 4V carb. I would not rev the motor at all without verifying the timing and that it is correct and by the book, that is a fast way to blow up your motor if it is too far advanced. The shunt is easy to make and the timing is pretty straight forward with a good timing light.

 

[enforcer30]

Re: Volvo Penta 4.3GL problems I'm Confused??

Alright guys I found a issue. I got my shunt and pluged it in, and after I warmed up the engine 600 RPMs, I hooked the lead to B+ and the timing did not change. I assume the timing should have changed. Am I correct?

 

[bjcsc]

Re: Volvo Penta 4.3GL problems I'm Confused??

Yes, it should have retarded...

 

[enforcer30]

Re: Volvo Penta 4.3GL problems I'm Confused??

Thats what I thought. So what component is failing? The module is new, but I know you can get a bad one. Is there anything else that would stop the advance?

 

[bjcsc]

Re: Volvo Penta 4.3GL problems I'm Confused??

I'm no expert, but I do have a factory service manual for the 1997 model of your engine. I would not expect that yours is different (but it could be). According to the manual, the module only has two failure modes: no spark and no spark advance. It doesn't sound like you're experiencing either. The 22deg you mentioned earlier is very close to the 23deg spec'd in the manual for your engine at 4600rpm. The only other component I can think of would be the pickup coil, but I am not Don S. enough to know whether it could cause your symptoms...

 

[Don S]

Re: Volvo Penta 4.3GL problems I'm Confused??

Be sure you hook up the shunt and hook the lead to a good 12V (B+) source. THEN start the engine. It won't work if you try it with the engine running.

 

[enforcer30]

Re: Volvo Penta 4.3GL problems I'm Confused??

Oh, well I will try that in the morning. This page said do not hook up the lead to B+ till after the engine is running.
http://www.marinemechanic.com/volvo/sb-34-2-5.htm

 

[Don S]

Re: Volvo Penta 4.3GL problems I'm Confused??

Sorry about that............... I was using the Volvo service manual, that says to start the engine after you hook it up.
But what do they know.

 

[bjcsc]

Re: Volvo Penta 4.3GL problems I'm Confused??

Oh, well I will try that in the morning. This page said do not hook up the lead to B+ till after the engine is running.
http://www.marinemechanic.com/volvo/sb-34-2-5.htm

That's interesting...when I check mine I do it per the manual (as Don S. described) and I have not ever caused the damage they warn about. I assumed that's how you did it when I posted last. I did notice in the manual that the procedure for EFI engines seems to involve attaching it while it is running - maybe that's where their confusion came from?

 

[enforcer30]

Re: Volvo Penta 4.3GL problems I'm Confused??

That is possable, I am going to go with Don's instruction. The guy just seems to know what he's doing. Heck at this moment I wish this boat was at his shop and not mine. lol.

Thanks again guys hopfully this issue will be over soon.

 

[enforcer30]

Re: Volvo Penta 4.3GL problems I'm Confused??

Ok I put the shunt in and set the timing to 6 deg. BTDC. Now from what I have read when I disconect the shunt it should be at 11 deg. BTDC @600 RPMs. However It is more like 17-22 deg. BTDC. Did I get a module that was bad out of the box????

 

[superpop]

Re: Volvo Penta 4.3GL problems I'm Confused??

Yup, sounds like a bad module to me.

 

[enforcer30]

Re: Volvo Penta 4.3GL problems I'm Confused??

Just got back from the lake. Improvement..... now I am seeing 4400 RPMs a bit over trimed but it is better. Timing is dead on. My question is I used a carb off of a 5.0 and my module came off a 2000 3.0. I believe they are the same, however if I am wrong enlighten me. Again I am working on a 4.3. The carbs looked identical, but is it possable the main jets are a little larger causing a rich condition?
All I need is 200 more RPMs getting close.

 

[bjcsc]

Re: Volvo Penta 4.3GL problems I'm Confused??

Just got back from the lake. Improvement..... now I am seeing 4400 RPMs a bit over trimed but it is better. Timing is dead on. My question is I used a carb off of a 5.0 and my module came off a 2000 3.0. I believe they are the same, however if I am wrong enlighten me. Again I am working on a 4.3. The carbs looked identical, but is it possable the main jets are a little larger causing a rich condition?
All I need is 200 more RPMs getting close.

I thought you said the module was new?? I don't know if the modules would be the same but I doubt it. I looked at the advance curves in the manual (3.0 vs. 4.3) and all points match except idle (3.0 is 10deg, 4.3 is 11deg)

It is very possible, actually very likely that the jets are different. What kind of carb is it? Should be a 500cfm Holley. Main jet:70, PV: 2.5

 

[enforcer30]

Re: Volvo Penta 4.3GL problems I'm Confused??

The module is new I just had it for a 3.0 I had worked on that turned out to be a coil. The sierra part numbers are the same. I have another one coming I just thought I might get my customer out for Labor Day.
As far as the jets go I am going to open the carb in the morning. I have the 70 jets and I will check the powervalve at that point.
Thank you again for the enlightenment, Barry

 

[enforcer30]

Re: Volvo Penta 4.3GL problems I'm Confused??

Ok I pulled the new carb apart and found 72.2 mains where as the original carb had 70's. The original carb had a 2.0 powervalve in it the new carbs powervalve has no number stamped on it. Could it be as simple as the 72.2's vs. 70's be my 200 RPMs?

P.S. again this new carb came off a 5.0

 

[Don S]

Re: Volvo Penta 4.3GL problems I'm Confused??

96 Volvo 4.3GL runs great accept it will not pull more than 4,000 RPM's after a overheat.

When did you change the carb, before or after the overheat did it go over 4000 before the overheat?

My guess is you had an overheat, and then it won't go over 4000 rpm is that correct??????????