The Stovebolt Site Forums The Parking Lot Big Bolts 57 261 WILL NOT START!!

I brought my first Stovebolt home about a month ago. It ran great almost everyday for about a month but suddenly won't even start. I have rebuilt the carb including new float, and replaced: fuel pump, inline fuel filter, battery, resistor, coil (MSD), spark plugs (gapped to .035), plug wires, 2 new condensers and 2 oem condensers, new rotor and oem rotor, new set of points and oem set of points, new cap and an oem cap. On top of this I have replaced all of the wiring and changed the oil. I have pulled the dist. and checked the shaft for wear... everything looks fine. It turns over, I can see fuel spraying in carb, and has good spark. But it will only backfire a little and on occasion will shoot a fireball out the carb. I have adjusted the timing a million times and no luck... any Ideas? I am 100% lost... THANK YOU!!

Hy MatBrindley, welcome, is your 261 in a big truck,or has it been transplanted into a small truck? Do you know the history of the engine/truck? Passenger car and light truck engines use a fibre cam gear, large truck engines and I believe all 261s use an aluminum cam gear. The fibre cam gears can fail, teeth can be ripped off of it, usually when this happens the engine will never run until the cam gear is replaced. It is possible that someone rebuilt your engine and used a fibre cam gear in place of the aluminum gear and that fibre cam gear has failed.
The only other thing I can think of is if you ran the engine with old gas varnish may seize some or all your valve stems in place. Take your valve cover off and check for bent pushrods. Good luck and please keep us informed of what you find.

The motor is in a two ton 6400 stake truck, as far as I know it is the original motor and it hasn’t been rebuilt but I don’t know much about the history of it. It has 98,000 miles so I wouldn’t be surprised if it has been rebuilt. I’ll take a look at the valves and pushrods tonight after work. I haven’t heard of that cam gear issue before, definitely something I’ll look into. Thanks for the info!

Compression, fuel and spark at the right time and it should run. It sounds like you’ve thrown everything but the kitchen sink at it without doing any testing. Since you say you have fuel and spark then the next thing would be compression. Get #1 up to TDC on the compression stroke and check to see what distributor tower the rotor is pointing at. Do a proper compression test, both wet and dry and report your findings here. You didn’t say how long it had been setting without running when you bought it. Stuck valves and bent pushrods are a real possibility. I know you’re frustrated right now but, slow down and test before throwing parts at it. Let us know your compression results. Good luck.

There is a logical diagnostic procedure for a "crank- - -no start" condition, one that works every time- - - - but it's one virtually nobody is willing to follow. Drop me a private message for more information- - - -I'm tired of wasting time listing it on the open forum.
Jerry

Why not just post a link to it, Jerry?

I had that happen once on one of my non-Bolts--Got it started for the first time in a lot of years--ran like a Swiss watch. The next time several weeks later it sounded like a John Deere tractor. Turned out some of the valves had stuck from the varnish in that old gas. Ended up replacing the gas tank, due to the amount of crud in the old one.

So I removed the valve cover and found 3 push rods that looked like pretzels. I pulled the head off, cleaned it out, replaced valve seals and push rods. Then I put it all back together, adjusted the valves and did a compression check, everything looks good. however, now it will start up fairly easy but does not want to stay running (almost sounds like it is misfiring). When I try to adjust the timing it is super inconsistent and I can't keep it in one place... any ideas what would cause this? A gentleman I work with who has experience with these motors said it could be a vacuum issue, any thoughts?