Hello brethren. I come hat in hand for help.. I bought this 61 truck with a 250 engine that was running great, a little smoke coming from the oil breather cap but idled ok and ran ok...just didn't have any guts. Well today I took it for a spin and it ran great. I noticed it was backfiring under load..not much Then I parked it.. I advanced the timing a bit and it was a bit better on a second trip to the store.. After the store it was getting hard to start and didn't want to idle so I set it more fuel on the carb screw(wire) Well it stared and idled but with a bit more RPMs. I drove home ok only a 1/4 of a mile tiny grade..no power... Lots of smoke then when I hit the red light next to my house lots of smoke coming from the breather cap,2 mins on the light and 30 seconds after green light I was home but as soon as I parked it,hissing, boiling... it said 240 degrees on the gauge. It seems like it's done for. I need help in the Vegas area to see it it can be dialed in better (if it still runs) Or another 250. I have lots of cool parts to trade,not a lot of money since Ive been out of work since Dec... Is anybody out there??
https://youtube.com/shorts/dULHD7anj2U?si=8oUMv2KZ3A5C10e4 https://youtube.com/shorts/JvtdkbehO_w?si=f3QpMlmSiEuqqRHT
Try tightening the intake, they have a habit of loosening and causing a vacuum leak. You might have a lean condition problem.
Too advanced of timing can make it run hot. Put a timing light on it and set to around 10-12 degrees BTDC. That should be a good amount to start with. Vacuum advance disconnected, just as reminder when using timing light. Backfiring could be too lean. Have you cleaned the carb to ensure no plugged restricted p***ages? Also checked to make sure good spark getting to the plugs?
Remove the plugs and do a compression check. With breather smoking, and no power sounds like a worn out engine with a ring problem. Before anything else the compression test needs to be done.
We'll just went out the there and it started and idle that was after I retarded the timing..but it still idling too fast... There might be hope still yet... Will mess w it tomorrow
What Jethro said about the manifold bolts. Tightening them was part of any tune-up you did on a Chevy 6 back in the 60/70's. If it's a points distributer, another thing to look for is play in the distributer shaft. The shaft rode directly on the aluminum housing and would wear it until the dwell would dance all over the place, especially if you revved it. Also made them hard to start when cold. And they pinged under load. Fixed mine with an HEI.
It's got timing gears and no chain but the stock fiber gears do **** out. I ran mine close to 300K in the 48 starting with a 74 engine with 95K on it. The engine was so worn out that it finally quit in town one day and didn't have enough compression to start. Still the guys pretty well nailed it. Compression test first Pop the distributor cap off and rock the crank back and forth to see if you do have slop in the timing gears or missing teeth. Check the distributor shaft for wear/slop.
It got it running again but I heard noise from the valve train so took the vc off and saw that #11 rocker arm is loose and it seems like they have the nut torqued down more than the rest.. I'll wait for further guidance thanks https://youtube.com/shorts/awAC6cUB6bI?si=3Z693Puan3R3GjAP
If it's a Rochester Model B carb, check the two big phillips head screws that attach the float bowl to the throttle plate. It's common for them to get loose and create idle problems. Regardless of what type of carb it is, make sure it's mounted securely to the intake manifold and that the mounting gasket is intact. Does your truck have a working choke?
It's an automatic choke I don't know how it works tho..it's not manual..my 2 350 che bites have a manual
Major operator error . Big **** up... I thought I was advancing the timing rotating the distributor like my SBC .nope I retarded it all the way down... Bent pushrod,,im old school I took a rubber hammer and straightened it ..it seems like it's all right now...I'm a dumb***
I also lost the acc spring return to the carb which I found in the parking lot...in my desperation to get home I just took it and shoved it somewhere and went home
It's running great now..thank you guys for all the help and the overused "keep trucking" meme..it always helps...I'm always learning from y'all
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