Loosen the valve caps and see if they are interfering with the closing of the valve. Some of the valve cap gaskets are thinner and the valve may just hit when cold, but when it heats up may have enough interference to keep the valve from seating. Check the inside of the cap for evidence of wear. Sounds like a condenser, but check the simple first. It also could be valve or seat wear about to become terminal. Good luck, Dan
Hard starting when hot
- Thread starter SteveW
- Start date
more info required on this- what carbs and what ignition?
Thanks for all of the excellant input. I checked the compression cold (50-55#) and hot (55-60#) tightened the carb's flanges, cleaned the plugs and their connections. It started right away after this trial but I could not start it after it sat for 10 minutes. After running it again and getting it hot I noticed that the engine was burbiling and spitting slightly so I re-adjusted the carbs. After another run and shutting it down, it started right away hot and also after 5 minutes and after 15 minutes of sitting. I (we) seemed to have licked the problem, but I still have not taken it out on a long highway run and seen what the results are. I have some carb insulators that just came in today and I will them install if there is a problem after a long highway run to see what the results are.
This forum is great, again many thanks.
This forum is great, again many thanks.
I had this prob on my Comet the mag had been recon'd by a well known expert it behaved for a while then I had the same problem very difficult to start when hot, I returned the mag this time it came back with a new slip ring fitted I was told that a batch of defective split rings had been identified , its been fine since.I must also say the expert replaced the part FOC.
Steve,
The compression figures you gave are very low. I think you may have cured several small problems with your checking that were exacebating the starting problem, but with less than half of the compression you need, I do not think the engine will be happy in the long run even though you have perked it up in the short run. I would still do a leak down test to see where the compresion is going. If you need new rings or a valve is not closing properly you will be chasing your tail by pursuing the carb adjustments much more.
Good luck!
David
The compression figures you gave are very low. I think you may have cured several small problems with your checking that were exacebating the starting problem, but with less than half of the compression you need, I do not think the engine will be happy in the long run even though you have perked it up in the short run. I would still do a leak down test to see where the compresion is going. If you need new rings or a valve is not closing properly you will be chasing your tail by pursuing the carb adjustments much more.
Good luck!
David
I agree, these comp. are way off. I checked them again, only this time w/ a hard gasket instead of the o-rings the comp. tester provides and they came up to 85-95#. (They should be w/a 7.3/1 c.r. around 124#) These pressures are not great, but better. I plan on doing a leak down test as suggested and see what the culprite is. Thanks again.
Possibly a silly question but are you opening the throttle wide open when doing the compression test?
Not a silly question, but yes I do have the throttle open when doing the compression test. I also tested it hot.
out side guess Atd worn not returning to retard