706 gas missing when hot

P T Farmer · Dec 2, 2013

Hi there. I have a 706 gas that starts perfect and runs smooth until it warms up and runs rough and misses. When its warm and pulling hard it sounds ok but goes back to missing under a lighter load. I"m thinking carb but maybe coil. I hate to mess up my great starting, any weather. Any thoughts would be appreciated.
Thanks.

John T · Dec 2, 2013

I cant say from here (heck even if there lol) based on little info what the problem is. That being said, Id look at the points and possibly condenser FIRST before suspecting or buying a new coil. Sure a coil can fail once up to temp, but a condensor can also act up when warm and burned pitted points perform worse. Ever pull a wire and look at spark quality once shes warmed up???

Is the gas flow out of any sediment bowl or in line filter to the carb good n steady????

If you open/remove any bottom carb bowl drain cock does gas flow smooth n steady n even???

Is the gas cap or tank vented okay so there's not an air lock as gas flows out of tank??? Run it a while with gas cap off n see if that matters??? Ive seen tanks or caps not vent and gas flow slows after a while!!

John T

charlieu · Dec 2, 2013

(quoted from post at 00:44:38 12/03/13) Hi there. I have a 706 gas that starts perfect and runs smooth until it warms up and runs rough and misses. When its warm and pulling hard it sounds ok but goes back to missing under a lighter load. I"m thinking carb but maybe coil. I hate to mess up my great starting, any weather. Any thoughts would be appreciated.
Thanks.

I'm (ALMOST) sure that your manifold gasket is leaking. Take a 9/16 box wrench and try to tighten up the bolts that fasten the manifold to the cylinder head, you should notice a difference in how she is running. This is a common problem with the 6 cyl engine. If the miss goes away with the manifold tight you may be able to get by untill spring when gasket replacement will be required. good luck

pete 23 · Dec 2, 2013

Times 2 on the manifold. I just love those manifolds. Took a jillion of them apart to clean the innards and repair heat riser. If you did it every time you did a valve job on them they came apart pretty good. Also, I like the gasket IH used later on with the embossed material on intake ports. Most exhaust manifolds need resurfacing and of course proper installation for alignment so as not to stress them to prevent cracking.

D7fever · Dec 3, 2013

if all the other suggestions don't work, check your valve lash, if too tight ,when hot will hold the valve open

P T Farmer · Dec 3, 2013

Hi again. Thanks for the replies. They will give me some things to try. On the manifold, wouldn"t I hear ticking on a cold start?

706 gas missing when hot

P T Farmer

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John T

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charlieu

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pete 23

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D7fever

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P T Farmer

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