Engine doesn't idle or start well after about 15 minutes of riding

I have a 1980 Motobecane Sebring with a Morini MO2 engine. When I bought it always started up fantastically and ran well. However after about 15 minutes of riding, it tends to die at stoplights (which is always great fun). Afterwards it is impossible to start for at least another 15 to 30 minutes. I have rebuilt the top end since then so I don't think it is a compression issue, it has a new carb on it and it doesn't seem to be a jetting issue, have tried new spark plugs, and the temperature gauge never gets above 340. Does anyone have any idea what is going on or what I should look at next? I'm definitely new to working on engines but I am at a loss as to why half an hour of sitting can be the difference between being impossible to start and starting on the first kick.

Re: Engine doesn't idle or start well after about 15 minutes of riding

Moped Lar (OFMC) /

Condensor is shot.

Re: Engine doesn't idle or start well after about 15 minutes of riding

Overpriced Parts /

Could be jetting issue if Rich

Did you do a full throttle plug chop with a new plug with chop open the plug and read it?

Re: Engine doesn't idle or start well after about 15 minutes of riding

Yes and it doesn't seem to be the jet.

Re: Engine doesn't idle or start well after about 15 minutes of riding

My guess is the condenser too, there are some good articles on re-routing the condenser outside the magneto on the wiki

Re: Engine doesn't idle or start well after about 15 minutes of riding

What are the benefits of an external condenser?

Re: Engine doesn't idle or start well after about 15 minutes of riding

A bad ignition coil another possibility. Dad could make three revolutions in the front yard and his Snapper lawnmower would just die but would restart after 15 to 30 minutes.

I would replace the condensor first as recommended since they should be cheaper than a a new coil but if the condensor doesn't fix the problem, my next guess would be the coil.

Re: Engine doesn't idle or start well after about 15 minutes of riding

The external condenser is away from the engine and wont heat up. It's the heat that kills those things.

Re: Engine doesn't idle or start well after about 15 minutes of riding

All right I'm going to try the condenser then. Thanks for the advice guys!

Re: Engine doesn't idle or start well after about 15 minutes of riding

Brent Bublitz /

Could be seals as well. Once the case heats up the seal starts leaking and you start running lean.

Re: Engine doesn't idle or start well after about 15 minutes of riding

i second that opinion. seals. it only has to be off a little when cold and when it heats it will multiply. the condenser is either dead or it's not.

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