1983 5.7li 350 Chevy

[OperativeK]

Im new to working on larger engines and this one is doing something I have never seen before. It begins to bog out at about 2000 rpm and above. It will idle perfectly I had recently rebuilt the carb and I can see that it is getting plenty of fuel. I replaced the coil and points. Any troubleshooting suggestions? Also no water in the fuel lines.

 

[calwldlif]

Re: 1983 5.7li 350 Chevy

Why did you rebuild carb?
Was the same problem there before?
Will the engine smooth out
above idle if you don't push throttle?
How sure of the rebuild are you?

 

[OperativeK]

Re: 1983 5.7li 350 Chevy

Rebuilt the carb cuz float what stuck. No didn't experience the same problem before. If I push throttle over idle to 1000 rpm it is smooth above slightly experience vibration and @ 2000 and above it sounds like it is struggling.

I just took compression on all and one cylindar is 130lbs while all others were 150 +-2.

Would the one cylindar do this? I would imagine a V8 being able to get above it no problem. The carb rebuild is all good.

Sounds like the timing is not advancing. There is no vacume tube for advancing and Im not savy on the electical system on this boat.

This fellas is identical to mine but mine is little older:
http://www.flickr.com/photos/palmsolo/sets/72157594196910128/

Could this be the stator?

 

[calwldlif]

Re: 1983 5.7li 350 Chevy

I am leaning tword the carb.
The float may be to low.
The reason is the problem was not
there before the rebuild.
Unless there is something else
you did.
What carb?
Power valve is trick on the rochesters
Accel pump is needed to get the
carb to flow from the mains.
I am still confused on the 2000 rpm thing.
Does it surge?

 

[OperativeK]

Re: 1983 5.7li 350 Chevy

No it doesn't surge, it is bogging down, sounds like the timing is not advancing but there is no vacume line to the distributor so Im confused on how to troubleshoot the timing. Thanks for the input. It ain't the carb.

 

[Cptkid570]

Re: 1983 5.7li 350 Chevy

Fuel pump? Are you sure it's getting enough gas at the higher rpm?

 

[OperativeK]

Re: 1983 5.7li 350 Chevy

Positive fuel is plenty. Not a fuel problem. Does anybody know how the electrical system works on this.?

 

[Reel Poor]

Re: 1983 5.7li 350 Chevy

The timing is all mechanical advance, there is no vaccum advances on marine engines (well almost none). Set point dwell then set base timming to specs. Bring engine idle up to around 2500 rpms and recheck timming, should be all in. If timming did not advance check weights and springs in the distributer.

I don't have the specs for you. I hope you have a manual.

 

[OperativeK]

Re: 1983 5.7li 350 Chevy

Posting Solution:

Found that after replacing the points the plate even though it is not suppose to be adjustable does have play in it that can rotate it few cm off retarding the timing.

I found out by loosening the plate and then retarding it one direction which made the problem worse and then I retarded it the other direction. Guess what all is well sounds beautiful again. I just love getting to know a engine. NOT! lol Thanks for the input fellas.

 

[DangerDan]

Re: 1983 5.7li 350 Chevy

Now that you have that all figured out I'd do away with the points & install an electronic conversion for a more trouble free system.