Im still battling a significant decrease in power between my green 712 and my tan. The green has significantly more power even with a Swiss cheese muffler and I can't seem to figure out why. I'd state it as low end power as the truck revs pretty well and performs decent at high rpm. Any advice as to what to try next would be appreciated.
Found no change of power converting to civilian ignition. Timed to 9degrees and had pinging. Came back to 7. I checked timing at 2500 rpms and I am not as advanced as I should be at that rpm, but bringing it any further causes ping.
Tried adjusting, and even swapping the carbs between vehicles and had no change. I noticed my idle surges after swapping them back but only very slightly. I don't think it's in the carbs as the problem did not change when swapped.
Compression runs about 125-130 a cyl. I'm confident I have the valves adjusted but I may need to take a second look to be sure. It also has a decent puff of smoke at startup which goes away when warmed.
The condition of the trucks chassis is fantastic but m afraid I may have worn cylinders, leading to the low power. Any ideas?
Trying to track down a lack of power
- audiocontr
- Posts: 1868
- Joined: Fri May 01, 2009 1:30 pm
- Location: Buffalo NY
Trying to track down a lack of power
1973 712m
1968 Haflinger
1965 Pathfinder
1978 GMC Palm Beach (Hey, its got 6 wheels!!)
1968 Haflinger
1965 Pathfinder
1978 GMC Palm Beach (Hey, its got 6 wheels!!)
Re: Trying to track down a lack of power
Have you checked the intake risers for cracks? We have seen them crack right at the base allowing air into the system and causing all kinds of low end problems. There are several variations of these risers. I am assuming that since the newer ones have more reinforcement, this must have happened to the Swiss also. The only way to really check them is to take off the engine tin and visual or spray with your favorite leak detector (brake/carb cleaner, wd ...)
Re: Trying to track down a lack of power
I had a significant lack of power when the timing was off. I'm sure you have checked this on yours but, that is where
I had a major increase when properly set.
I had a major increase when properly set.
Any man who thinks he can be happy and prosperous by letting the government take care of him:
better take a closer look at the American Indian.---Henry Ford
better take a closer look at the American Indian.---Henry Ford
- audiocontr
- Posts: 1868
- Joined: Fri May 01, 2009 1:30 pm
- Location: Buffalo NY
Re: Trying to track down a lack of power
I did actually check the risers. I sprayed and looked for cracks but found none. I expected more volatility from the brake cleaner and carb cleaners (I tried both). They didnt cause the engine to surge when i sprayed into the carb, instead it bogged. I may need to check again with something else, but i did attempt it after removing the tin.
I guess im back to the distributor. I'll keep on trying. Thanks for the input!
I guess im back to the distributor. I'll keep on trying. Thanks for the input!
1973 712m
1968 Haflinger
1965 Pathfinder
1978 GMC Palm Beach (Hey, its got 6 wheels!!)
1968 Haflinger
1965 Pathfinder
1978 GMC Palm Beach (Hey, its got 6 wheels!!)
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- Posts: 1704
- Joined: Wed Apr 14, 2004 3:42 pm
- Location: San Bernardino Ca
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Re: Trying to track down a lack of power
Try looking down the carbs with the air box off. Look for fuel dripping onto the throttle plates while idling and then after shut down. If you see fuel dripping, either the float is leaking or the float valve is not seating. Also since you have 2, try swapping the distributors. If that makes an improvement in running, the advance mechanism may be sticking.