I have a Subaru Robin ex21 that will only run when I have the choke on and I have my hand over the air intake on the carburetor I've Got a Brand New carburetor installed new plugs new oil check the governor and throttle linkage everything's correct it'll only fire up and die what is going on please help me fix this issue
Please help
- Thread starter TJNokes
- Start date
Brianator
Gettin' er done!
Is there a mixture screw? If so back it out a bit and see what happens
bob58o
SuckSqueezeBangBlow
Carb issues aren’t that difficult if you think logically.
It runs better when you cut off the air supply. That means either it is getting too much air or not enough fuel. I’ll assume you already made sure that fuel is getting from the tank to the carb.
Possible Reasons for too much air:
Air leak
Air screw backed out too far
Possible Reasons for not enough fuel:
Dirty Carb / Clogged jet or passage
Jet too small
Fuel screw turned too far in
90% of the time “runs better with choke” means an air leak or dirty carb. 10% of the time it needs a jet change. Depends if it is a stock carb and if other people messed around with it prior.
Since your carb is new. I’m 99% sure you have an air leak (unless you have an aftermarket exhaust - then it probably needs a bigger jet).
Tape off most of the air horn to get it running. Then spay some starting fluid around the gasket area. If the RPMs change when you spray - you have a leak.
PS. Make sure you have the engine idle speed turned up high enough. A new carb might have the idle speed screw backed out too far for you engine. Just make sure you got someone on the brake or have it pressed up on a tree/wall/... so it doesn’t run away on you.
It runs better when you cut off the air supply. That means either it is getting too much air or not enough fuel. I’ll assume you already made sure that fuel is getting from the tank to the carb.
Possible Reasons for too much air:
Air leak
Air screw backed out too far
Possible Reasons for not enough fuel:
Dirty Carb / Clogged jet or passage
Jet too small
Fuel screw turned too far in
90% of the time “runs better with choke” means an air leak or dirty carb. 10% of the time it needs a jet change. Depends if it is a stock carb and if other people messed around with it prior.
Since your carb is new. I’m 99% sure you have an air leak (unless you have an aftermarket exhaust - then it probably needs a bigger jet).
Tape off most of the air horn to get it running. Then spay some starting fluid around the gasket area. If the RPMs change when you spray - you have a leak.
PS. Make sure you have the engine idle speed turned up high enough. A new carb might have the idle speed screw backed out too far for you engine. Just make sure you got someone on the brake or have it pressed up on a tree/wall/... so it doesn’t run away on you.
pearl111
Well-known member
Thanks bob580 this helps me also I'll print and keep in shop for reference notes.