SD40 succumbs under pressure

[Krondor]

Hey Guys,

I have got my engine running to the point where I feel comfortable to drive it.

Idle Vacuum is around 18 inches, Engine RPM is around 500, timing is on the small round BB @7' degrees BTDC.

For a cold start, I can keep the choke off, turn the key, and it will start right up. Is this normal? My problem comes into play when I press the accelerator pedal. I have to play a game with it to accelerate without dieing. How long do I need to warm the engine before driving? Am I overlooking something?

Thanks.

 

[63cruiser]

You and i are in the same boat assuming you have checked your valves once you get the engine hot. If you have done that. i think you might be in for a rebuild. It has been very frustrating for me. i think i must have a blocked passage or needle. Mine had ran great but then i had my head gasket repair and it sat dry for a month or so. Must have introduced something along the way to block the fuel to the to the intake. Do you get a nice stream of gas when you pull up on the accelerator linkage? i am no mechanic and i get a little lost when reading the FSM when it starts talking about the low speed system, high speed system, power system and accelerator system. Not sure when one kicks in to the next stage. Clearly my low speed system appears to be working but not sure where my problem is after that.

 

[oregon fj]

Mine takes a long time to warm up. Carb was rebuilt by Mark (@65swb45). While it will start with little to no choke when cold, it can't be driven that way. I run with a little choke for at least 5 minutes driving, if not more.

 

[Krondor]

You and i are in the same boat assuming you have checked your valves once you get the engine hot. If you have done that. i think you might be in for a rebuild. It has been very frustrating for me. i think i must have a blocked passage or needle. Mine had ran great but then i had my head gasket repair and it sat dry for a month or so. Must have introduced something along the way to block the fuel to the to the intake. Do you get a nice stream of gas when you pull up on the accelerator linkage? i am no mechanic and i get a little lost when reading the FSM when it starts talking about the low speed system, high speed system, power system and accelerator system. Not sure when one kicks in to the next stage. Clearly my low speed system appears to be working but not sure where my problem is after that.

I have checked the valves while the engine is hot and everything is within spec. The engine will idle perfectly but when I initially try to press the accelerator, the engine will stall out. I have to let it warm up for a pretty long time before it can be driven. Then the acceleration is fine. I have rebuilt the carb already and ran wire and brake cleaner through all the passage ways so I believe the carb should be good. I get a solid stream of gas when I pull on the accelerator linkage. That's why it is confusing me a little.

Mine takes a long time to warm up. Carb was rebuilt by Mark (@65swb45). While it will start with little to no choke when cold, it can't be driven that way. I run with a little choke for at least 5 minutes driving, if not more.

That's good to know that it takes a while to warm up. This is my first vintage vehicle and I am still learning the quirks and what is technically normal.

 

[unklwedy]

Sounds like exhilarator pump ain't working. and possibly to rich.