engine problem advice (yamaha 2001 15hp 4 stroke)

[thescotsman]

Hi Lads,

Took the boat out Sunday for its second outing of the year, for the kids to search for basking sharks.
Anyway, typically after being no trouble at all for the past few years it conked out after a few seconds when I started it at the slip. Thought it might be flooded, so left it a few minutes and restarted it, whereuopn it did the same thing again.
Noticed there was a bit of fuel coming out, so when I took off the cover, I could see fuel leaking from the engine (dropping out of bottom of housing for carburettor. More came out when I pulled the rope or pumped the bulb in the fuel line.

Seems to me like something was jammed open or something? Anyone any ideas. Want to get the kids out asap and don't fancy waiting to get it looked at this time of year by a mechanic if its something I can do myself. I'l probably strip down the carb tonight to check, but if anyone has an idea what might be wrong, or whether I'm wasting my time I'd be delighted to hear from you.

Cheers,
Lee

[MAC]

2 things I can think off.

Hold off with the carb strip for now as you might damage a gasket and need to replace.

Were you using old Fuel? Some of the old fuel in the fuel lines might have gummed and could be causing a blockage. Try drain the Fuel out of the carb and lines. If there is a small white inline filter, check for dirt or water and replace if necessary. You can also flush it in some old fuel if your strugging to get a replacement quickly.


You might have some damage to some of the fuel lines. Easily replaced. I think that engine uses 6mm internal diameter fuel line. Bring some into a car supplies store and they will seel you some by the meter. Might be a nice time to replace the tank lines as well as it's cheap stuff.

One or both of the above will hopefully work.

Let us know if it works.

Kev

[yngkmd]

i had the same thing happen on my motorbike recently (also a yamaha)
turned out is was the carbs all blocked up with gunk but they were given a good cleaning and all systems were go.

the engines may be on different vehicles but the same basic principles of the internal combustion engine should still apply

[JimC]

Sounds similar to a problem I once had. Needle on the float was unable to seat due to some shite and therefore the engine tended to flood itself. A clean out sorted the problem.

[thescotsman]

Thanks for the replies guys. Tried starting it tonight and it ran as sweetly as it has for the past few years . I guess something was blocking it, but the ride home must have dislodged it??

Anyway, just to be sure I followed the various leads you gave me...

Fuel was pretty new, half a tank from the run out in Feb and the rest filled on Sunday. Tank was in garage in the intervening time. Checked the fuel lines etc and they were all clean, gave them a blow through with the compressor as well to be sure.

So, I took the carb off, and removed the bottom of the float chamber. Took out the float and checked the needle, filter etc. Everything was pretty clean, no sign of any gunk/dirt etc which suprised me to be honest.
The bottom of the chamber did have a tiny deposit building up around the drain screw, so I cleaned it off, checked the rest of the carb and stuck it back together.

Anyway, started fine again, and ran on idle for 15 minutes and higher revs for 5 mins in a barrel again with no issue.

As I say, I assume something had blocked it somewhere and just become dislodged on the way home, but definitely worth checking to put my mind at rest. Might change the fuels lines etc anyway as its probably a good thing to do.

I'll give it another run tomorrow evening just to be sure....

Thanks for the tips guys.

[MAC]

Good news lee