5.7 L Volvo penta GL 3800 RPM WOT

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I have a 2002 5.7 L GL Volvo Penta in a 1994 2030 SST Chaparral with a Volvo DP C1 1.95 out drive. I cant seem to get anymore than 3800 rpm. Have tried props from B4 - B8. B8's being way to much and B4's still wouldn't turn any more RPM. Have rebuilt carbs new fuel filters new fuel pump and fuel lines. Tried new gas still no change. It almost seems to lose RPM when its full throttle the I pull back a little on the throttle and it picks back up. Any suggestions ?
 

alldodge

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Most cases you start with the basics, check compression. If compression is in the 150 psi range then go to timing and fuel pressure.

Since this is happening at WOT I would put a fuel pressure gauge in line with the carb and verify you have 4-7 psi at idle and 3-7 psi at WOT.

If fuel pressure checks out then I would check settings with the carb, float level, jet size, power valve and leaks. Check vacuum
 
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Thanks ! will start there. Forgot to mentioned that when i could start it meaning its been sitting for months it takes a lot of cranking to get to fire at all then once it fires that first time starts on first touch of the key the rest of the trip meaning week long trips. Then every blue moon i go to start and there is no power to the ignition just dead check connections etc. and for no rhyme or reason its back on. Changed ignition switches and seem to correct it then it happened again on the last trip. Not sure if the 2 problems could be related i doubt it but you never know I guess Thanks again sorry for long response:)
 

alldodge

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Many times the no start issue comes from the slave solenoid, not always but many times
 

alldodge

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Would the slave solenoid cause there to be no power in the gauges as well?

No, it would only cause a no start. If your loosing gauges, I would start from the battery cables and remove and clean all to bright shinny metal. The main issue in most cases is the ground cable, and not just the battery terminal, also check the block connection
 

Scott Danforth

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agreed on checking fuel pressure.

did you take the carb in to get rebuilt, or did you do it yourself?

also, double check your timing. 10 degrees BTDC for base at 650 RPM, you whould be at 28 degrees BTDC at 2800 RPM

the taking a long time to crank upon sitting is the fuel needing to get back to the carb. I am willing to bet your accelerator pump circuit is leaking down (dirt in the passages.)
 
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Rebuilt myself which believe me Ive thought could be an issue. Thanks for info will be checking all these things. determined to figure this out before summer this time. Just checked ground connections noticed that the cable is partly melted in a spot that is next to exhaust manifold. Not sure if that could cause intermittent power loss to all gauges and stater but will replace for sure.
 

Maclin

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The throttle-back response sounds like maybe the secondaries are opening too much, could be a tuning issue like this if it is a 4bbl carb.
 

Scott Danforth

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The throttle-back response sounds like maybe the secondaries are opening too much, could be a tuning issue like this if it is a 4bbl carb.

or the secondary is opening, however there is no fuel in the bowl, or the fuel in the bowl isnt getting to the venturis.

is this a holley carb or rochester
 

Silvertip

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There is an adjustment that is very well hidden on the secondary air valve spring. If that adjustment, or the spring is not installed correctly, you get exactly the issue you are having. I don't have any pictures of this part of the carb so you will need to find a good GM factory service manual for any vehicle that used the quadrajet carb.
 
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Its a 2 BBl carb so that wouldnt be it. Going to check compression put new plugs and wires check timing have a mechanic rebuild the carb this time. Then lake test. Hopefully will have it fixed this month or at least eliminate those things.
 

bnicov

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Check your cap and rotor. I had a similar problem. Turned out the cap was a mess. Mind you, mine would backfire and really act strangely.
 

jimmbo

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When you cleaned the carb, did you clean out the metering orifices used in the power enrichment circuit? They are on the metering block and accessible when you remove the power valve. I've had those clog. Also check to see that the power valve doesn't have a ruptured diaphragm.Other than that, the 500cfm Holley is a very good carb on that engine. As mention before, check to see if the timing advance weights are free to move
 
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