Mariner 15 outboard problem

[sunquest]

After 7 years of faultless running, my Mariner 15 2 stroke is misbehaving. When idling the engine revs up normally. Under load, the engine will tick over OK but on acceleration the engine usually dies although sometimes it will rev with a little aggressive throttle action. I have replaced the spark plugs which has improved things marginally but at the moment all I can do is potter around at tickover. Thanks in advance. Geoff

 

[VicS]

I'd suspect a carb clean is required.

Try pumping the fuel line bulb. If that helps it might pointo a defective fuel pump or air leaking into the fuel line.

Try operating the priming pump ( choke) if that helps it points to a dirty carb.

Have you checked the sparks. You should get strong blue sparks able to jump at least 3/8 " If not suspect an ignition fault

 

[sunquest]

I'd suspect a carb clean is required.

Try pumping the fuel line bulb. If that helps it might pointo a defective fuel pump or air leaking into the fuel line.

Try operating the priming pump ( choke) if that helps it points to a dirty carb.

Have you checked the sparks. You should get strong blue sparks able to jump at least 3/8 " If not suspect an ignition fault

I won't be able to test your suggestions until I go to the boat on Sunday, but in the meantime do you think it possible the HT leads are breaking down? I remember many years ago I had a similar problem with a car which turned out to be the HT leads. As the engine revs freely in neutral would this suggest a fuel problem? Thanks Vic. Geoff