Problems with the Walbro 997 carb

[toot]

.hi guys. i need .help with a walbro 997 carb.the problem is the high and low speed .needle's are turned all the way in and idle screw as well .the motor runs fine like this but what worries me is it not running to lean. when i back out the low jet the motor dies. is this a leaking gasket on motor or carb related,23 cc zenoah with new piston and barrel. thank you

 

[Mick Mars]

I would spray some brake clean around manifold ,carb base ,if idle increase probably have a leak. If no increase set idle so throttle plate barely open, pull air cleaner so u can see,set mixture screws at factory settings. Choke closed should pop after 2/ 3 pulls ....open choke should fire 2/3 pullz then go from there.There are some great feads in one of the threads,I think under general engine questions

 

[toot]

I would spray some brake clean around manifold ,carb base ,if idle increase probably have a leak. If no increase set idle so throttle plate barely open, pull air cleaner so u can see,set mixture screws at factory settings. Choke closed should pop after 2/ 3 pulls ....open choke should fire 2/3 pullz then go from there.There are some great feads in one of the threads,I think under general engine questions

thanks for the input

 

[spents]

.hi guys. i need .help with a walbro 997 carb.the problem is the high and low speed .needle's are turned all the way in and idle screw as well .the motor runs fine like this but what worries me is it not running to lean. when i back out the low jet the motor dies. is this a leaking gasket on motor or carb related,23 cc zenoah with new piston and barrel. thank you

if the needles are all the way then it shouldnt really run fella,
either the needles have been over tightened in and thats damaged them, and damaged the seats,
or they've been damaged and someones tried to re grind the needle tips making em shorter,
or the needles aren't actually all the way in,
if i were you i'd unscrew the needles and remove em and have a close look at the tips for damage first off

 

[toot]

thanks i will check

 

[TODD]

Another thing to check is if the carb isolating block is flat? They have a tendency to warp and even on brand new engines from Zenoah I have checked and were warped bad.

 

[toot]

Another thing to check is if the carb isolating block is flat? They have a tendency to warp and even on brand new engines from Zenoah I have checked and were warped bad.

thanks did check no problem there