Volvo Penta 3.0 GS Problem.. RICH.. Pics too

[87baylinercapri]

Greetings,

Just aquired a 96 four winns 170 horizon with a volvo penta 3.0 GS with only 30 hours on it. I am having a seemingly "running RICH" issue. The engine idles rough, gets a little better as it warms but still rough, and wont go WOT, it stumbles all over itself past 1/2 throttle. I found something that is interesting to me, since i dont know anything about CARBS but the Choke plate stays closed or "choked" all the time, the only time it even starts to open during normal operation is FULL throttle. even then it only opens 1/8 of the way. this seems like why the motor is running like poop. When it's idling the choke plate just flapes between closed and 1/8 open. When you choked the engine it doesn't do jack to the choke plate, when you fully choke it, the choke plate slightly opens to 1/8 position...is this right? Below are some pics...

Throttle at "FULL THROTTLE" , in gear, normal operation.

 

[Hitech]

Re: Volvo Penta 3.0 GS Problem.. RICH.. Pics too

While I have very little experience with boat engines, I do have experience with carbureted engines. Having the choke stay on will cause a very rich mixture (that is it's function). Typically, the choke should open if you open the throttle, even when the engine is cold. After the engine warms up the choke should be completely open. Yours sounds like it is not operating properly.

 

[tommays]

Re: Volvo Penta 3.0 GS Problem.. RICH.. Pics too

The choke is electric and should start opening when the key is on

If its not the coil is bad OR its not getting 12 volts or has a BAD ground


Tommays

 

[Don S]

Re: Volvo Penta 3.0 GS Problem.. RICH.. Pics too

You won't have any power to the choke coil with the switch in the run position and the engine not running, the choke coil is powered from the AC tap off the alternator. Which also means if your alternator isn't working, neither is the choke.

 

[Daddy O]

Re: Volvo Penta 3.0 GS Problem.. RICH.. Pics too

That was a problem with GM cars. If you lost a alt. belt the choke light would come on, describing the problem that Don S. gave.

 

[87baylinercapri]

Re: Volvo Penta 3.0 GS Problem.. RICH.. Pics too

is it safe to run the motor without that air filter thingie off??? it seems like its a flame arrestor or something. I guess that's the only way to find out. either way, the engine is definately running pig rich. anything else to look for if not the choke coil?

 

[Don S]

Re: Volvo Penta 3.0 GS Problem.. RICH.. Pics too

No it's not safe to run without the "FLAME ARRESTOR" all it takes with a rich running engine is a backfire from a bad ignition system (see your other post about needing a distributor cap) or a bad carb, a bad fuel pump and you have an explosion.
Why it is running rich needs to be found out. If the plate is closed as you explained in your original post, WHY? ? ? ? Don't just look for easy suggestions, troubleshoot the system.
Of course to do that properly, you will need an OEM Service Manual, or a few days/weeks of asking opinions and slowing giving all the details so the cause of your underlying problem surfaces.