Yamaha advice needed

[wazza66]

Decided to take the wife and 2 little ones out for a day on the water this morning in the 445 Dory Quinny.

I left the ramp after I started my 2005 40hp Yamaha and noticed it was very smokey after starting( blue) and just thought as I had been doing a bit of trolling last weekend that the plugs might have been a bit oiled up.

Got about 500m from the ramp at idle speed and lost all power.

Thought it might be a fuel problem, so check all the line/bulb and even swapped to the spare fuel line.All connections are good as well as the fuel line. This still didn't fix the problem.

Ended up getting towed back to the ramp by another boatie (thanks alot again if you read this).

Come home and pulled all of the fuel lines from the motor and cleaned the fuel filter out.Reassembled and put another tank of fuel onto the line and it seems to be running (roughly ,however but not stalling) but blowing a heap of blue smoke from the prop/muffler area.

I can see a oilly slick around the back of the prop.

Can anybody help me diagnos my problem before I have take it to a mechanic.

I would like to fix it myself if possible.

Any help would be greatly appreciated.

Cheers

Wazza

[BM]

Sounds possibly like an over oiling issue. I assume that its oil injected? If not this does not apply.

There are 2 problems an oil injected Yammy can suffer. The oil injection system is typically very reliable however the seal on the oil pump itself can let go (causes the bottom cylinder to have excess oil) which results in hard starting and excessive smoke.

The other problem is a check valve in the oil line lets go and no longer holds pressure which effectively results in the same situation. Oil gets pumped into the intake manifold of the relevant cylinder.

Would seem unusual to occur on such a new engine.

Cheers

[Ron173]

I had a big Merc do this once before, plugs were the issue.

Also mechanic told me once they oil up they are generally stuffed unless you have a proper sand blast plug cleaner.

When you consider that plugs are the most highly stressed component in your engine, I'd be putting a new set in first before progressing this one.

Rgds

Ron

[wazza66]

BM

Thanks for your reply.

I ran the motor tonight and it idles better (still a bit rough) after running new fuel and blowing out the rubber hoses around the fuel areas.

I also cleaned the plastic fuel filter attached under the oil resivor and noticed a bit of crap in it.

Seems to be a bit of black oil/residue around the prop/muffler area still.

It still blows blue smoke from the prop and I am thinking of giving it a run at high revs tommorrow night on the Nerang River to burn the oil off, but am a bit cautious of breaking down again!.

What do you think??.

Any other advice???

Cheers

Wazza

[Ron173]

BM

Thanks for your reply.

I ran the motor tonight and it idles better (still a bit rough) after running new fuel and blowing out the rubber hoses around the fuel areas.

I also cleaned the plastic fuel filter attached under the oil resivor and noticed a bit of crap in it.

Seems to be a bit of black oil/residue around the prop/muffler area still.

It still blows blue smoke from the prop and I am thinking of giving it a run at high revs tommorrow night on the Nerang River to burn the oil off, but am a bit cautious of breaking down again!.

What do you think??.

Any other advice???

Cheers

Wazza

like previously said, I'd be replacing plugs..... a simple cheap option before going deeper

Ron

[BM]

Wazza,

That sounds like an excellent plan to me. Go out alone and give it a flat strap run for a MINIMUM of 15 minutes.

You are only at risk of stalling and non restarting when running at low speed. All engines are susceptible to failure at low rpm when there is a problem. Think about it, its logical. The engine is running

[BM]

Wazza,

That sounds like an excellent plan to me. Go out alone and give it a flat strap run for a MINIMUM of 15 minutes.

You are only at risk of stalling and non restarting when running at low speed. All engines are susceptible to failure at low rpm when there is a problem. Think about it, its logical. The engine is running at its lowest possible speed so it only takes the slightest upset in fuel mixtures and it will say "nope, not playing"........

Higher in the rev range and you typically won't have a problem (unless you had a fuel starvation issue) but that does not typically occur at idle speed, unless under the worst possible circumstances.

SO............ go for a nice long thrash at flat knacker (or WOT for the tossers, and even as a mechanic I hate the WOT thing), then run her low down as anyone would and see what you have. And then check it the following day also to look at the potential oiling issue.

By the way. W&W on the other forum site is an exceptionally good mechanic and is an OMC Master Technician (and knows his Mercs and Yams) so perhaps don't dig too hard (he meant 2 stroke, not 20).

Cheers