1995 5HP Yahama Overheating

[Wibble]

I hope someone can help with this.<br /><br />I have an 8 year old 5HP Yamaha 2 Stroke which is giving me some problems. It runs fine for around 30 mins but then starts to occasionally misfire and eventually the engine backfires and stops running. It can usually (but not always) be restarted after this but it happens again after a few minutes.<br /><br />The problem seems to be less noticable when I leave the engine cover off which makes me thing it is related to the engine temperature. The engine is air cooled so I'm a little confused as to what the problem might be.<br /><br />Any ideas?<br /><br />W

 

[Jammu]

Re: 1995 5HP Yahama Overheating

8-year old aircooled ????

 

[Wibble]

Re: 1995 5HP Yahama Overheating

I was told it was round about 8 years old but I don't know for definite. It is air-cooled though. <br /><br />Any idea what the problem might be? I suspect it's some kind of compression issue. Would the symptoms be consistent with that and is a complete overhaul the only way to solve it?

 

[MurdockJr]

Re: 1995 5HP Yahama Overheating

I didn't know Yamaha made an air cooled engine<br />but I may be wrong.

 

[Forktail]

Re: 1995 5HP Yahama Overheating

It could be anything from the premix you're using (100:1 recommended), to fuel vent, fuel pump, carburetion, or ignition problem.