I have a older terramite with a Briggs and stratton 16 hp cast iron engine that has been converted to run on a car coil. The engine has been running great, the only problem is that it backfires sometimes when shutting it off. Today i was clearing some land and it started running rough all of a sudden, cutting out under load, backfiring though the exhaust. I got it home and started playing around with it. It fires up no problem and runs like a top at idle. when I throttle it up it spits and sputters and backfires. It cuts out if I try to move it when it is at a higher idle. I have tired to adjust the carb with little to no improvement. I changed the fuel filter, gas looks clean. I have recently went through the entire engine, new head gasket, lapped an adjusted the valves, cleaned the carb, new plug and plug wire, throttle springs, etc. not sure what is would cause it to all of a sudden start running bad. Any suggestions?
Engine idles fine, stumbles and backfires when under load
- Thread starter parluskq
- Start date
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davesl708
Elite Member
Sounds like a timing issue or possibly a governor adjustment problem.
I may have found my problem, I will no know for sure until tomorrow when I can test out, but I think its with my points. I took my points cover off and I noticed that the isolator was loose. and when i move it down it crosses over with will cause the coil to fire every time this happens. Now i am not sure why it would idle fine then stumble when revving up the engine unless the vibration is causing it to cross over. I am hoping this the problem.
DJ54
Elite Member
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- Tractor
- IH Farmall 656 gas/ IH 240 Utility/ 2, Super C Farmalls/ 2, Farmall A's/ Farmall BN/McCormick-Deering OS-6/McCormick-Deering O-4/ '36 Farmall F-12/ 480 Case hoe. '65 Ford 2000 3 cyl., 4 spd. w/3 spd Aux. Trans
I see you had the discharge nozzle out. Did you check & clean the tiny cross drilled holes in it..??
quick update... So i cleaned the carb and reset the point gap, after some adjustments it ran better for about 20 seconds. then quit... i then could not get it to even idle good. i did notice around where the points are some arcs from around the adjustment bolt (not a good sign) to make a long story hours of tinkering and the only thing i ended up with was a stripped plastic starter gear and sore legs. I did get it started, with a pull start, long enough to limp it back into the garage. I am going to pull the flywheel tonight and send it to briggs tomorrow so they can re-polarize it and I will switch it over to an electronic ignition.
bigdeano
Platinum Member
Sounds like the condenser has failed.
I tried a new one and it did't change anything. I pulled my flywheel last night and am shipping it to briggs today so i can change it over to electronic ignition.
kencunningham
Silver Member
- Joined
- Apr 21, 2009
- Messages
- 197
Have you filed the points? My onan power case 446 wouldnt start and i filed the points with a emery board and it still wouldnt start. I could work the points manualy and i could see the spark, but it wouldnt start. I remembered reading somewhere about cleaning the points with paper and tried that, cranked right up and ran fine. Try pulling a pc of clean paper thru your points after they have been filed and reset to proper gap.