Help Volvo 3.0gs popping thru carb

[dlbryant1]

Need help please. This thing is driving me crazy! This is what I have tried.

Compression 150psi all four cylinders.
Replaced distributor
Plugs & wires
Removed exhaust elbow & intake exhaust and water tested for cracks and replace gaskets
Removed burnt exhaust flapper
Replaced wore out camshaft and lifters.

Everything I have done made it better but I am still left with a small amount of a pop when first second of starting and when I get above 3500 rpms the popping thru the carb gets really bad and I start to loose power. The engine does not like to idle real well but just off idle all the way to 3000 rpm runs great. This engine has had a water pump failure in the past and has been hot enough to melt the hydraulic lines going the trim cylinders oh yea replace the lines also. This boat ran ok at first of season up until 4th July.

Questions

What is sticky valves or valve pop?
What will wear the cam exhaust lobes off of #3 & #4 cylinder?
What happens when you have a small crack in the water jacket in the exhaust leaking into the exhaust port?
What will cause one not to run good on factory set timing. I have to set by ear before run well from 1200-3000rpm. Just like old days.

Thanks for any help

 

[Don S]

Re: Help Volvo 3.0gs popping thru carb

What year?
You also can NOT set the timing on the EST distibutor by ear, it just can't be done
You MUST used the timing shunt shown in the service manual to put it in base timing mode and then set it exactly by the book for your particular year. Then take it out of base timing mode and run it. Don't put the timing light back on to check, cause it won't tell you anything.
Then, set the idle mixture on the carb and the idle speed to specs.
Depending on the carb, you may also need a power valve.

 

[dlbryant1]

Re: Help Volvo 3.0gs popping thru carb

I do not have a second plug on the dist so I can put the two wires together. My boat does not have the shift asist. Were can I get the second plug or can you tell me wich two pins to short together. I have tried riding down the lake with someone driving with changing the timing all the way for ping to it does not want ot run still have pop,

3.0gs PNCA 1994 -2000 not sure but I think it is 1995. The cover said to set the timimg to 1 deg. There is also a good white mark on but pieces.

I am going to check fuel pickup and fuel pressure next and rebuilb carb.

 

[Don S]

Re: Help Volvo 3.0gs popping thru carb

Like I said earlier, you can't just move the distributor around to set the timing unless you put it into base timing mode first, and I know you don't have a shift interrupt switch or a second plug on the distibutor with white wires in it. That is a Mercruiser, you have a Volvo.
Read my post, I said you need a special shunt (Volvo Penta PN 885163) that will plug into the distributor.
You also have an NC model 3.0GS which is a 96 model year engine.

 

[dlbryant1]

Re: Help Volvo 3.0gs popping thru carb

Thanks for the shunt number I will get one now. Can you tell me why the cam might have wore.

 

[dlbryant1]

Re: Help Volvo 3.0gs popping thru carb

Found head gasket blown between #2 & #3 clylinder after camshaft installation. Cam wore because when engine overheated the valve stems were sticking in valve guide. Replace motor.