yamaha 40 hp 2 stroke owners required

[beamishken]

Hi I posted a question a couple of weeks ago but still not resolved the problem i have with my 2001 yamaha 40 veto 3 cylinder 2 stroke when on tick over the engine runs on 2 cylinders move the throttle forward and the lever on the side of the cdi moves up and it goes onto 3 and the revs pick up general opinion is that it should run on 3 all the time but tried another cdi unit and no different swapped coils no different
i'm not totaly convinced that it isnt supposed to do this and would like to here from another owner if theres is the same its number one cylinder that goes off at tickover (i have herd of other engines shutting down individual cylinders to achieve a low enough idle speed

there must be someone who has one of these who can pull no 1 plug lead off and convince me one way or another

come on guys HELLLLLLLLLLLLLLP

cheers

[Jizm]

never heard of the yam triples shutting down to two on tickover before

pilot jet in the carb blocked?

[spartacus]

I've not aware of it running on 2 cylinders at tickover. There is an auto-choke on the Yamaha 2-stroke Autolube. After starting it will automatically lower the revs after initial start-up.

Try posting the same question here - on the forum. Their technical guys may be able to help. Be as descriptive as possible, giving the age of the engine, model number, etc.

http://yamahaoutboardparts.com/

[beamishken]

cheers for your input guys but its definately spark related as there is no spark on no 1 cylinder untill you lift the lever on the cdi unit then its like you switched the cylinder on



i'll try the link posted by spartacus

thanks

[Jizm]

the lever on the cdi is adjustable, make sure it is set to the spec in the service manual.

[beamishken]

cheers jizm but the adjustment would only alter the time/throttle position when the cylinder cuts in what i need to know 100% is should the engine drop on to two cyls at tick over or not if not what could be wrong with it?

everyone says "dont think it should or never heard of that before" but nothing 100"% what i realy need is for someone with the same engine to pull off no1 plug cap at tickover and say mine does/doesnt do the same

thanks
ken

[Jizm]

ring yamaha direct, they are usually very helpful.

[9D280]

Unless it's fuel injected and so fuel can be cut as well as spark, shutting down one cylinder will do nothing apart form oiling up said cylinder.......

[beamishken]

Hi thanks for the input guys
I did speek to yamaha who could only suggest taking it to a dealers and pluging in the diagnostic computer but I havent had chance yet & there isnt a dealer localy i'd trust

BHG were most helpfull and sent me a used cdi unit on sale or return but it made no differance

I take the point about fouling the plug but it doesnt the engine ticks over reasonably once warm and picks up straight away once you open the throttle I tried screwing in the idle screw on no 1 cylinder as it doesnt run on it so doesnt need fuel (or so i thought) but the engine then starts to missfire on no3 & eventualy drops that cylinder must be a ballance port across the crankcase

so still not convinced I know it sounds illogical to anyone familiar with the workings of an engine (me included) but i have herd of this before on a small suzuki 3 cyl 2/ which dropped a cyl on idle

still need an owner with the same engine for a comparison

anyone recommend a good honest dealer in either the north east england or north ayrshire
scotland

regards
ken

[jyasaki]

It is possible to get the software and kit to run the diagnostics yourself. Not real cheap, though, as I remember. I think it runs on a laptop, but have no idea how it plugs into the computer... (needless to say, I haven't done this.)

jky