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I'm having difficulty with my 52 M38 at higher ambient air temperature; >90. She initially starts fine, runs great until slowing down from highway speeds to an idle; then doesn't want to idle, sometimes quits. Also, it is then more difficult to start, but once it gets going does fine again at highway speeds.

On cooler days, runs perfect.

I'm kind of scratching my head on this one. I've considered fuel tank/cap venting, re-adjusted the idle; tried leaner and richer, and considered float level. Engine temp runs a solid 180. Any thoughts would be appreciated.

Jim

Check the heat riser under the intake. May be stuck in open (heat on) position.


The little gray arm with the round end on it.

Thank you very much Wes, I'll take a look.

Jim

Wes, my heat riser is toward the valve cover and all the way in the up position and I haven't drove it in acouple of days . Would that be correct position or incorrect. Thanks John jr

Should be towards the fender. Is it frozen or free?

Wes, it's free but definitely towards the valve cover. Can this be put on backwards. Drove it alittle today and it seems like it was starting to sag down . Will try to get a good picture of it. It also looks like it has a small piece of asbestos tied onto it for some reason. Thanks John jr

The mechanism can be assembled incorrectly and the only way to be sure is to split the intake/exhaust and look at the valve. To troubleshoot try tying it first full travel one way then the other and test drive it.

Wes, thanks I will try it. John jr