Motor choking

I have a Volvo Penta AQ145A in a 24 foot Berretta. The boat starts up just fine and takes off great, but after about 5 to 10 minutes it becomes sluggish and starts panging. No knocking or panging prior. It has a new gas tank, carburetor and water separator. The oil is new.

It has a breather hose that comes off of the crankcase and hooks up to the carburetor. I took it off the hose after 10 minutes and it is blowing a lot of smoke (blue). When it is off the motor seems to do fine, but the engine compartment fills with the smell of oil.

It seems like the breather hose is choking my carburetor (1 barrel). Can I add a vent to the oil cap and block off the hose coming off the crank case to the carb?

Can I dill holes in the top of the flame arrester to get more air?

Any ideas?

Re: Motor choking

Also it does not overheat. No water in the gas or oil. It has never been sunk. Friends say it is just too much boat for that little 4 cyl motor. The marina mechanic agrees, but has a 6 cyl for me which I will pay him to install.

Re: Motor choking

Ayuh,... My guess is the New carb ain't doing any better than the old carb did...
In other words,... It sounds like it's Still, Starving for fuel...

Forget about the breather tube, it's Not your problem...
If the flame arrester isn't plugged with Crap, it ain't your problem either....

Re: Motor choking

Thanks. That is what the mechanic said too. He thinks they rebuilt the solex and sent it back to me. What a pain. New carb is way expensive.

Re: Motor choking

It has a breather hose that comes off of the crankcase and hooks up to the carburetor. I took it off the hose after 10 minutes and it is blowing a lot of smoke (blue). When it is off the motor seems to do fine, but the engine compartment fills with the smell of oil.

It seems like the breather hose is choking my carburetor (1 barrel). Can I add a vent to the oil cap and block off the hose coming off the crank case to the carb?

Click to expand...

What you need to do is a leakdown test and find out what is wrong with the engine.
Drilling holes and adding vents is right up there with putting a bandaid on a gunshot wound.

Re: Motor choking

LOL to the bandaid. These are all great suggestions.I'll see if the mechanic at the Marina will do a leakdown test, and I'll mess with the mixture close to shore. He says it is a Pig in the water. Doesn't like the carb. I would much rather change the intake and carb then to get a new motor. I don't need to go fast, but the panging sound does not sound good. I will try all of them and report back.

Re: Motor choking

You need to find out why there is so much blow by. I have the same problem with the starboard engine. Runs fine at higher RPM does not like to idle and loads with oil on rear Solex. Compression test shows that #4 cylinder has only 50 lbs of pressure. If your compression is good then the next step is to check the oil trap and replace if needed.
Looking for a short block myself.

Re: Motor choking

This forum is incredible. I wish I would have signed up a year ago.