2008 yamaha f40 runs good for short time,then idles

[Twostrat]

I have a video . In the video i went about a mile down the lake and it went from running to idling.

Here is a link i uploaded to dropbox
https://www.dropbox.com/s/pygxdyun5y...60945.mp4?dl=0

Motor cranks and runs great..it has no certain time when it will start to idle. I have ran it 10 minutes and then it will start. I have ran it 3hrs and then it would start idling.

I was told it was getting hot and going in limp mode. I not sure. The heads are not hot and the water pump is new. And the water stream is not hot...it was doing the same thing before i replaced waterpump.

I would like to know what to check? Any ideas would be appreciated.

[99yam40]

what RPM are you calling idle

[TownsendsFJR1300]

Couldn't play thru one browser, can see it now thru IE!

[Twostrat]

Im new at this bare with me..

The idle speed that the engine goes to is the rpm where you can shift gears with.no problem.
When you put it in gear it acts like it bogs down and has no power..

The video works on my end its 100MB it will take a few seconds to load... i know its upside down...

Thanks for you help.

[Twostrat]

4.24.2016 video yamaha f40 2008

Here is another link to a different video?

https://www.dropbox.com/s/3bgawkfl7l...20f40.mp4?dl=0

If this link does not work here. Try copy and paste to a new tab. In your browser..

I have never had any trouble when first crank and head out . The trouble always starts later. And it will never happen.at home when i can check it out.
In the 4.24.2016 video i went down the lake about 15 minutes, half throttle, fished couple hours and heading back it started when i cranked it up.. it has no certain procedure to stop running.. .i have been going down the lake at half throttle and it will start all of a sudden.
When it sits overnight it runs good at first. I have flushed engine, checked thermostat, it opens and closes, checked this by using hot water..while out of engine...

Thanks

[TownsendsFJR1300]

Disregard as the video was now visible..

[pstephens46]

Did all the 2008 motors have carbs? Quite a few F40s listed on boats.net.

[TownsendsFJR1300]

Did all the 2008 motors have carbs? Quite a few F40s listed on boats.net.

Yep, a quick look at ALL the F40's show roughly half carbed, half injected..

OP, we need a complete model # to proceed..

(Tks Pat, missed that altogether)

[99yam40]

yep I see the videos.

looked like he needed to pump the primer bulb at one point to make it better.

At this point I would check fuel pump pressure/vacuum

[TownsendsFJR1300]

Ok, got it to open on IE...

Agreed, once he primed the bulb it ran good. There's a fuel issue of some sort going on, fuel pump, or FI system(or air leak)

For the OP, we still need a model # but, if you keep priming the bulb, I gather there is NO more running issue..You can try that to confirm if you like....

Have you done any recent work to the engine, running gear?.

[Tony Harper]

Looking at the cowling shape it appears to me be a Fuel Injected model, if this is the case, then I recently had a very similar problem with a Fuel Injected Yamaha F 40, this one that I did was a 2012 model, here I Aus, we didn't get the Fuel Injected model until 2009, you say yours is 2008 ??

We definitely need your model number !!

Anyway, my 2012 F 40 EFI problem was fixed by removing & replacing the high pressure fuel pump mounted inside the VST, the new fuel pump comes with a new fuel filter that attaches to the intake of the fuel pump inside the VST, you can by this filter on its own, but here in Aus it was about the half the cost of the fuel pump/filter assy combined, so I replaced the fuel pump/filter combined & that has fixed this engine's fault.

PS the original VST efi fuel filter was very clogged up & fitting a new fuel filter only, may well have fixed the fault, however, because the cost difference was only minimal, I replaced both, because if the filter replacement only didn't fix the fault, then the VST would have to be removed again & then a new fuel pump purchased which included this filter anyway, therefore the end cost would have been more, plus extra labour to do the same job twice.

[Twostrat]

Fyi. Me pumping the fuel primer had no effect on the running of the motor.

Yamaha 40 hp
Model# F40LEHA
6BGL 1001512
Man...11/08

This engine has fuel imjection.

If you.need any more info let me know.

[Twostrat]

Have not done any repair on engine.
The foot and waterpump was replaced.
I was having the same trouble before and after the foot replacement.

[Tony Harper]

being the Fuel Injected version engine, I would be looking at the fuel pump fuel filter inside the VST, make sure it is not dirty/clogged up, they are very fine gauze, then if that is ok, you would need to check fuel pressure whilst the engine is at fault point.

[TownsendsFJR1300]

Plus 1 ^^^

Here's the link to your VST and filter...

2006 and Later F40LEHA Yamaha Outboard FUEL INJECTION PUMP 1 Diagram and Parts

As posted, check the fuel pressure when running, I suspect it's low to nill when acting up..




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