Winnebago dodge 440 running issues

[jab2373]

I am having issues keeping the engine running, it starts cold but about a min later it seems as if it just looses power, if you give it gas it hesitates then stalls. I thought it might be getting to much gas, I pulled the carb and checked the floats and needles but found them to be clean and working, could it be something with the timing? It also backfired through the carb while i was giving it gas to try and keep it running.

[dougbfresh]

Chances are it's the carb, especially if it sits a LOT. What carb does it have? Thermoquad or Holley? Do you have a timing light (an adjustable one even better), you can check the timing and advance. Also try to check fuel pressure/volume.

[jab2373]

It has a thermoquad, and I don't know if the year would help but its a 77.

[dougbfresh]

Jets are probably all junked up. What kind of vacuum do you have at idle (not just the value, but is it STEADY). Check the basics 1st, timing and vacuum.

Read this and check the scenarios at the bottom-you can tell a lot about an engine from vacuum readings:

http://www.secondchancegarage.com/public/186.cfm

[olddog]

Originally Posted by jab2373

I am having issues keeping the engine running, it starts cold but about a min later it seems as if it just looses power, if you give it gas it hesitates then stalls. I thought it might be getting to much gas, I pulled the carb and checked the floats and needles but found them to be clean and working, could it be something with the timing? It also backfired through the carb while i was giving it gas to try and keep it running.

If it was rich the engine would chug and blow black smoke out exhaust. The backfire is likely due to a lean condition. Likely looses power as it warms up and the choke starts to open, allowing it to go lean.

As Doug said the jets are most likely plugging up with degraded gasoline. You may try a heavy dose of SeaFoam if the tank is not too full.

[jab2373]

Thanks guys, When I had the carb off I also checked everything else, I cleaned it and reinstalled it, now to check what you recommended.

[olddog]

If the hoses are original, you could have a lot of vacuum leaks. If the power brake booster diaphragm dried up and cracked, it can cause a major vacuum leak.

Also the vacuum advance on the distributor can go bad (vacuum leak as well as timing issue). The plate in the distributor can stick. The centrifugal advance can stick and springs can break.

Hopefully it was just a dirty carb.

FYI - the old time big block Mopars were excellent reliable engines IMO, and I fly a Ford flag now days.