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unpredictable idle fix ?

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Jer

Jer

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Just incase someone else is having fun with their idle being all over the map I thought I would share this discovery -
Ever since I got my Midget in july 2006 the idle was always a gamble, I checked for vacuum leaks around the carbs, tried adjusting what I could etc. then I thought my throttle cable might be worn & grabbing a bit - went to take the air cleaners off last week (to repaint them)& by chance noticed that the entire manifold seemed to move a little when I put the wrench on the air cleaner bolts - sure enough the manifold bolts had backed off & here is what the manifold gasket looked like when it came off - I guess this may have affected my idle just a tad ? When I got the car the engine had only 600 miles on a rebuild - I had re-torqued the head bolts, my bad for overlooking the manifold. Did a compression test 170,165,160,170 & pressure held so it looks like I didn't burn up a valve (I'm assuming a loose manifold can't be a good thing) - The plugs looked a bit lean, very light brown. Now I just need to wait 3 more months for the snow to leave & I'll see what it runs like with a new gasket ...all seems so obvious now.
 

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Jer, it's a good idea to check those fasteners on a regular basis, such as every time you check the oil in the dashpots.
Given your numbers, I doubt if you hurt anything internally.
Jeff
 
Good point Jeff, I have been religious about the dash pot oil, I will add those bolts to that routine... and so the list grows :smile:
Thanks
 
It almost looks by the gasket that the ferrule "ring inserts" (Moss pp7, part #25)between the head and the manifold were omitted (causing the deterioration seen in the pix!). Were they there?
 
The rings were there when I opened it up - the only thing I can think is that the frontmost & rearmost bolts were a bit more snug than the rest, so the exhaust manifold didn't fall away as bad as the intake did - I know what you mean, the intake contact areas were total garbage...
 
Jer, it wouldn't hurt to check a couple of things further.

1. Make sure the intake and exhaust manifolds are the same thickness at the contact points of the washers. An uneven mating surface here won't allow the thinner of the two to be tightened sufficiently.

2. Make sure that the surfaces that mate to the head are flat.

Jeff
 
Thanks Jeff I'll do that - both good ideas... and the exhaust manifold did have some repair done somewhere along the way (I seen some braze on it... didn't look close to see if the flange areas are messed up), manifold gasket is ordered - I'll be sure to check everything you mention before wasting another gasket :smile:
 
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