2010 F40 Driving Us Crazy

[BigMikeSr]

My F40 (6BG20102001010868) had the VST replaced under the R&R program but it has recently been giving me problems again. Took it to the authorized dealer and every time they take it out it runs great.

Here's my scenario: I am a walleye fisherman in the Detroit River, most of the time handlining with my 9.9 kicker. Twice this fall I started my daily trip, motor started and ran great out to the area that I fished that day. Turned the 40 off and *****ed with the 9.9 for an hour or two. Decided to move so I fired up the 40 which promptly stalled. Started right back up but if I gave it any gas (tiller handle) it just sputtered and would not rev up. I kept the 9.9 running and crawled back to the dock, all the while with the 40 running, the tiller handle cranked wide open but could only get (guessing) 1200 to 1500 RPM max. Back at my well a couple of days later, the 40 started right up and revved up easily. Went out fishing and the same scenario happened again. Pulled the boat next day and took it in. It's still there but now it's December so they can't take it out in the bay to try it again. When they took it out a few times before all the gauges they had hooked up read normal. WTH?

Anyway, talking to my auto mechanic today, he said it sounds more like an electronics problem. He's had the same problem over the years with cars.

Anyone have any suggestions?

[ausnoelm]

"sounds like" is not in the trouble shooting manual, you need someone who knows what he is doing, and get it fixed properly.

[BigMikeSr]

At this point, everything is a 'sounds like'.

BTW, both motors run off the same fuel tank. Fuel runs to a water separator which then feeds two different fuel lines. Also changed the squeeze ball on the 40's fuel line. Fuel filter was clean. No water in the gas.

I'm considering trading in this motor for a brand new one. I can't trust it anymore. My granddaughter is almost old enough to take fishing so I need a motor I can trust.

[greasyshaft]

At this point, everything is a 'sounds like'.

BTW, both motors run off the same fuel tank. Fuel runs to a water separator which then feeds two different fuel lines. Also changed the squeeze ball on the 40's fuel line. Fuel filter was clean. No water in the gas.

I'm considering trading in this motor for a brand new one. I can't trust it anymore. My granddaughter is almost old enough to take fishing so I need a motor I can trust.

could be sucking air through the filter setup, do you have a fuel tap that you open when using the auxiliary? what is the fuel pressure at time of failure?

[BigMikeSr]

The 9.9 runs off the same filter and I have NO problems with it. No shut-off valve for either motor. Can't tell about the fuel pressure because every time it's gone out with gauges attached the motor runs great. It has never failed for the technician.

[greasyshaft]

Does it only do it after running the 9.9?

[BigMikeSr]

Yes. BUT.......that's the way I fish. Standard procedure. I rarely go out on only the 40. One more point to throw into the mix....the last time out I was running the 40 on a remote tank with a completely different, dedicated fuel line. I originally thought that maybe the 9.9 was suctioning the fuel from the 40 so I changed the ball. Didn't help.

It's puzzling for sure. That's why the possibility exists that it could be the electronic control module.

[99yam40]

easy to test when it is happening to prove if spark or fuel pressure is a problem
Throwing parts at it and hoping can get expensive

[BigMikeSr]

Called Yamaha Customer Service today and got the answer that I expected. Take the VST apart and inspect/clean it. Even though the fuel tank has a filter, there is a water separator filter, plus a fuel filter on the motor, their answer was that particles can still get through and plug up the Vapor Separator Tank.

Skeptical of that answer. They say that it is extremely rare that electronics is the problem.

[rodbolt17]

answer is good.
yep Yamaha and a few other overseas manufactures don't have electronics issues.

find a real tech.

but we have seen the updated fuel pumps fail.

[BigMikeSr]

To be fair, my guy is a real tech. It's just that the weather here is not conducive to test drive a boat this time of year plus the birth of his daughter plus their business being one of the busiest in our region. Since the beginning of October he has only had a few days where it was possible to take the boat out. October and November have been two of the coldest we've had in years and years. Sometimes I wish that global warming stuff was really real.

[BigMikeSr]

As for electronics issues.....the 25 Honda I used to run blew a board that cost me $800 to fix.

[99yam40]

You know what they say boat stands for, you are lucky is was only $800.

Had to replace the CDI on my C40 and it was only around $400 just to fix my motors idle problems. Timing was retarding to much at idle.
So there are problems with Yamaha's from time to time. Just make sure before spending the money

[rodbolt17]

I have been doing this for almost 30 years.
in that time I could fill several pickum up trucks with ign coils,stator and powerpacks that I have replaced on mercs and jonny rudes.

ALL the stators,pulser coils,ign coils and powerpacks(cdi units) that I have done on yamahas would fit in a shopping bag. like I say, find a real tech.

look on the techs wall for school certifications. should have at least 5 of them.

[BigMikeSr]

Rod, you got my curiosity up so I went to Yamaha's website to look up the Certified Master Technicians. My guy is on their list.