yamaha 50 stalls under load

[SailingT]

Hi wonder if anyone has any pointers for me to try before it goes off to be repaired.

Engine is a late yamaha 50hp 2 stroke now with tiller fitted, the engine ran well today on the boat with new fuel in the tank.

When in the water later it idled fine in neutral, but once in gear would only go at say 1/4 power at full throttle. Later on though as soon as you put it into gear it stalled and would not run. In neutral though it still runs perfectly with no load?

Anyone have any experience/ ideas please?

[cam]

My Yamaha 50 (4 Stroke High Thrust Edition) also did this (last used about 9 months ago due to exams etc) It has since been dramatically serviced but if you get any ideas I would also like to know

I found that trimming helps this but since its a tiller I cant help, sorry

[SailingT]

No problem Cam
Ill put up any results I find
Like you this hasnt been used for a bit. Im thinking it could still be fuel related or some crud in the carbs. Although ive had that before and it didnt behave like this

[warder54]

Just a thought, sounds like idle jet is clear but main jet clogged?

[spartacus]

Check the fuel pump. Could be a worn diaphragm. While you're there check the fuel pipe connections that the 'o' ring seals are intact and not dislodged, and the primer bulb goes hard, etc. You can drain the carbs at the fuel bowl to look for contaminants before progressing to full carb strip down.

[SailingT]

Appreciated guys

Thanks ill look into those things before I admit defeat and take it to the pro's

Strangely tried it again this evening and will now run in gear but still only about 1/4 throttle when its flat out, but will no longer stall in gear. In neutral its still the same as before perfect. Its pumping water really well and sounds nice, just wont open up still/ hasnt got the power.

[whisper]

Water in carbs?

[SailingT]

Not ruling anything out yet, although wouldnt have thought it was water as has been running a couple of hours with new fuel so a fair bit has gone through.
Like I said though not ruling anything out as of yet so cheers though

[Nightfisher]

As stated above Fuel Pump, High Speed Jet.
Perhaps Clogged fuel filter,fuel tank not venting enough. All in all fuel starvation or a bad secondary plug high tension wire, coil, bad plug... Good luck.

[dave3235]

Originally Posted by Nightfisher

As stated above Fuel Pump, High Speed Jet.
Perhaps Clogged fuel filter,fuel tank not venting enough. All in all fuel starvation or a bad secondary plug high tension wire, coil, bad plug... Good luck.

Hi

Check plugs after runing make sure there not wet.

[jyasaki]

Pumping the primer bulb while increasing RPM should tell you if it's a fuel draw issue. Won't tell you if things are clogged (at least not definitively) though.

jky

[robert hates h2o]

Oil injection model ??

[Roflhat]

I had exactly the same problem this week with my yamaha 70 2 stroke tiller. Check the carbs, take out all the jets and clean them. Use carb cleaner/airline through them and a thin wire if you can find one (from a wire brush etc) to put through the holes in the jets

[SailingT]

Just as an update turned out to be slight water/ crud in the centre carb, as soon as it was cleaned out it ran beautifully again. So back to 100% now.
Thanks for the help Guys