Engine starts only with air cleaner removed

[Papakina]

This is a rather recently developed problem on a boat that, having been purchased not that long ago, is still in the process of exposing its gremlins. The engine is a Universal 44 in a Cal39. After cranking a few times with no success I removed the air cleaner and it started right up. Then I brushed off the air cleaner and put it back on and it ran fine. Later I took the air cleaner home to clean it. Removing the rivet to bend back the screen I found nothing inside. My last boat, a Cal25 has an Universal M12. That air cleaner came apart and inside was a spongy material that could be cleaned. This one is essentially an empty box with a screen on the intake. Has this been modified? Should I put some material in it? Should I replace it with something else? Anyway - now every time I start for the first time in the day I do the drill of trying to start it with no success and then remove the air cleaner and then it starts. I then replace the air cleaner and it runs fine. Starting later in the same day is no problem. What does this indicate? Bad compression? Grumpy gremlins?

[rwidman]

Originally Posted by Papakina

................. Later I took the air cleaner home to clean it. Removing the rivet to bend back the screen I found nothing inside. My last boat, a Cal25 has an Universal M12. That air cleaner came apart and inside was a spongy material that could be cleaned. This one is essentially an empty box with a screen on the intake. Has this been modified? Should I put some material in it? Should I replace it with something else? ...........

If it were mine, I would start by replacing the air cleaner with a new one. One specific for your model engine.

Then, If you still have the starting problem, do some additional troubleshooting.

[JPA Cate]

You might take a look at the fuel in the carburetor. If your air cleaner used to have that foam stuff inside, I have seen it degrade and little bits of it get in the carb. Clean the carb, re-set the idle to the manufacturer's specs, and see what happens. It seems like a fuel to air ratio kind of problem to me, but I'm no expert.

A.

[Steve W]

Ann, the Universal 44 is a diesel. No carb.

[JPA Cate]

Thanks, Steve,

Our old Universal was an Atomic 4, a thousand years ago, give or take.

Good thing I didn't tell him to clean the plugs, huh!
Ann

[Blue Crab]

Ann, your advice was excellent, except for that ONE little thing.

[Panope]

Perhaps the removal of the air cleaner has nothing to do with the problem. Maybe the time interval that elapses (during the air cleaner removal) is somehow helping with starting.

BTW. My air cleaner (like yours) has nothing inside.

Steve

[rwidman]

Originally Posted by Panope

.............BTW. My air cleaner (like yours) has nothing inside.

So how does it clean the air?

[Zanshin]

It doesn't, but it has very little air resistance. Seriously, I believe someone just removed the filtration unit at some point in the past. My first boat with a Yanmar had the same thing, an empty filter; but in that case I believe the P.O. (a charter company) was just saving money.

[Panope]

Originally Posted by rwidman

So how does it clean the air?

It doesn't.

I was using the term "air cleaner" for continuity with the OP. I think a better name for this unit would be "intake silencer".

Also, Mine has a hose attached that connects to the crankcase breather.

My set-up is bone stock from the Yanmar factory. I think that Yanmar believes that a boat operates in such clean air that a filter is not necessary.

Steve

[Blue Crab]

The Owner's Manual on my ~1980 YSM12 Yanmar indicates a poly filter inside the Silencer. My Silencer is missing but I use a rubber radiator hose with a hunk of coarse poly foam with a hose clamp.


http://www.ship468.org/boats/Catalin...t%20System.pdf

[rwidman]

I think I would be looking for the proper element for the air cleaner/silencer. The air in a boat's bilge isn't that clean.

A few dollars to protect a multi thousand dollar engine seems like a good use of funds.

[Tellie]

The three Cs of diesel
1) Clean fuel
2) Clean oil
3) Clean AIR. Use the right air filter.

Sounds like a cold start problem with a restricted air intake. Once it's warm it starts easier even with the existing air screen somewhat blocking air, not uncommon. As stated above, replace with the approved air intake filter.

[Blue Crab]

It's the common green soft foam filter material. Open cell.

[capngeo]

I've got ~3000 hours on a Yanmar with NOTHING on the intake