The Stovebolt Site Forums The Shop Area Engine Shop Help with engine miss.....

Gentlemen and ladies,

I'm looking for some help with a miss that I have in my engine. My truck is a 1966 Chevy C-10. It has a 250 6 cylinder motor in it. I replaced the carburetor with a remanufactured carb after months of trying to adapt a Holley/Weber progressive 2 barrel to it.

When I got it all back together it now has a miss. The miss is most pronounced at cruising speed. On acceleration it is still there but not as noticible. It causes the truck to feel like it is lurching when you are trying to maintain a speed.

Last night I checked the compression ratio on all of the cylinders and the were all in the 170-175 range. I put new plugs and plug wires in it. (I converted it to electronic ignition with a Petronix ignitor a while back. That is why I did not do points and condensor.) Tonight I'm planning to play with the timing, adjust the carburetor, and check for vaccuum leaks.

Any other ideas or thoughts?

Thanks,
Mike K.

Too lean?

A miss at steady speed, cruising, is possibly a too-lean condition. Is there enough fuel? I.e. the fuel pump works and the filter isn't clogged? Is the float set right?

Good luck!
George

I have checked the fuel pump with a vaccum guage and it was up to specs. I'll check out the other suggestions.

Thanks for responding.

Mike K.

Mike: I know you said ya put new plugs and wires did you check gap, go out after dark open hood and see if any wires might be grounding or if you have bad connection. I've found this problem before on 6's and 8's. popcorn The Truth is Out There (Just because they are new they might not be right.)

I would look for a carb that has not been touched and have it rebuilt,I read a artical that those companies that reman carbs throw everything in bins and make a generic carb. Each carb is made for a specific cubic inch and the reman companies dont put the parts back in the correct carb,you will get a fuel bowl for one size and the throttle plates and internal parts for another and have a carb that will not work right. If you have the original carb rebuild it or find another for your motor,you will probably not get that reman carb to work right. Jeff

Sounds so obvious, but, check to see that all the plug wires are fully seated down on the distributor cap. I had a plug wire that wasn't staying on the distributor cap....it would slide up out of the slot because the rubber cup was not in the right place.

Good luck!

Thanks for the replies.

I checked the plug wires by pulling each off the spark plug while the engine was running. Each was getting fire and each caused the engine to miss worse.

I think it is the carburetor. I have the original carb still as I had an extra that I used for the core. I'm going to put it back on and see what happens. I'm seeking a good carburetor man in the St. Louis area to take them to to have fixed. There is one on South Broadway that I may use. I'm waiting on a reply from a club member who told me of someone he recommended.

Mike K.

Mike K, i heard mention about gap size, new plugs, wires and making sure wires are seated right, how about right wire to right cylinder, sounds simple enough but that's what it sounds like. jake 51' 5W

Ahhh....good post Jacob. Sometimes we do overlook the obvious! Hopefully one of the easier fixes will cure the problem.

I am south of St. Louis about 70 miles. Years ago (about 20), I had to have my carburator cleaned NUMEROUS times (until I finally figured out it was dirty gas from my tank). There was an OLD guy in Crystal City, Mr. White, that was the best at carburators. Every time I took it to him, he'd take it all apart, clean it, reassemble it, and charge me only 5 bucks! Mr. White has since passed away.

I'm lucky that in my area (Farmington area) I have a great network of automobile "specialists" to get parts, have work done, etc.

Good luck!