Hey all,
I'm usually the one giving advise, but right now I really need somebody's opinion as I am wasting more and more money and this project is in the way.
I have a 1974 Briggs 5HP some people may remember from my build thread awhile back. This motor ran great for one weekend, until it just stopped. It began running very rough, not idling, not revving, just firing at high throttle and stopping. It was running the pulsa jet back then.
I have since swapped the carb to a 22mm mikuni copy, and have tried a tecumseh dellorto - non adjustable.
I have bought a genuine Briggs coil for 60 bucks, and swapped the flywheel from my 1990 5HP. I have pulled the head, checked the timing but have not been in the crankcase for a bit.
I have no idea what the problem is. It fires now but wont run. With the tecumseh carb, every pull-over results in a series of backfires. This leads me to believe the problem is at the valves. do I have a bent valve? how do I know? Compression is still great. :hammer:
I have swapped over half of this motor and still have no joy. Any help would be appreciated here. Do I pull the head or sump? last time I pulled the head everything looked good, maybe I should have checked more thoroughly on the valve side of things? Everything in the spring box area looks good, and both valves go up and down. :thumbsup:
Motor does not knock, only mod is a Billet rod.
I think the valve or valves are bent. What are your thoughts?
-Jack
I'm usually the one giving advise, but right now I really need somebody's opinion as I am wasting more and more money and this project is in the way.
I have a 1974 Briggs 5HP some people may remember from my build thread awhile back. This motor ran great for one weekend, until it just stopped. It began running very rough, not idling, not revving, just firing at high throttle and stopping. It was running the pulsa jet back then.
I have since swapped the carb to a 22mm mikuni copy, and have tried a tecumseh dellorto - non adjustable.
I have bought a genuine Briggs coil for 60 bucks, and swapped the flywheel from my 1990 5HP. I have pulled the head, checked the timing but have not been in the crankcase for a bit.
I have no idea what the problem is. It fires now but wont run. With the tecumseh carb, every pull-over results in a series of backfires. This leads me to believe the problem is at the valves. do I have a bent valve? how do I know? Compression is still great. :hammer:
I have swapped over half of this motor and still have no joy. Any help would be appreciated here. Do I pull the head or sump? last time I pulled the head everything looked good, maybe I should have checked more thoroughly on the valve side of things? Everything in the spring box area looks good, and both valves go up and down. :thumbsup:
Motor does not knock, only mod is a Billet rod.
I think the valve or valves are bent. What are your thoughts?
-Jack