My Volvo Penta 7.4gi revs high and smokes

[2000Penta7.4gi]

Hello Forum,

An odd thing happened last night. All of a sudden, my engine started to rev really high and smoke was coming out of the engine compartment.

I opened the hatch and found a black cap (off the manifold - I think it is the manifold) down in the bulge.

There was oil that sprayed onto the bottom of the hatch and onto the exhault on the starboard side (which is probably where the smoke came from).

I checked the throttle linkage and it works fine.

Any ideas on why the high revs and why that cap is off?

We just got our boat back from service and they don't work on weekends. Brutal.

Thanks all.

 

[BLinindoll]

Re: My Volvo Penta 7.4gi revs high and smokes

what manifold? exhaust? intake? what does the cap look like? oil cap? did you put the cap back on and was it fine after that? need more details.

 

[2000Penta7.4gi]

Re: My Volvo Penta 7.4gi revs high and smokes

Blinindoll,

The cap is black and looks like an oil cap, but it's not that one. The oil cap is on. I can see where it came off. There's a place in the manifold/cover where is twists and locks back on. It's the cover on the opposite side that has the oil filter and oil dipstick. It's the side that has the circuit breakers and the flame arrestor.

Attached is a picture of the cap.

I did not put it back on and start it because I was afraid of the high revs.

Thank you for responding. My family is sitting here looking at me like "what the heck dad, let's go" ha

 

[2000Penta7.4gi]

Re: My Volvo Penta 7.4gi revs high and smokes

Ok, I went online to see if I could find an expanded view of the Volvo 7.4gi and I found one. The cap that came off is the valve cover cap. The oil filler cap (which is the same cap) is still on where it is supposed to be.

Is that area under pressure where if the valve cover cap came off then it would spray oil through that opening?

Why the high revs? Any ideas on that?

Here's the picture of the cap again (the first time it was too big of a file).

Any help would be greatly appreciated.

Stranded Father.

 

[BLinindoll]

Re: My Volvo Penta 7.4gi revs high and smokes

i didnt realize there were 2 caps. there should only be one. maybe im just not familiar with the 7.4l. if the cap came off the valve cover, oil might tend to splash out. as far as reving higher, it shouldn't do that if the cap that youre describing comes off. might be another issue. somehow the motor is getting more air then it should, like a large vacuum leak or bad intake or carb/tb gasket.