Carb help!
Thread Starter
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Joined: Jun 2015
Posts: 79
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From: Lake Placid Florida
Carb help!
My 79 is hard to start after sitting overnight. Ive rebuilt the carb and tuned, filled the bowl overnight with no leakdown but still have to crank for 15-20 seconds before starting in the morning. Any advice?
Thread Starter
Advanced
Joined: Jun 2015
Posts: 79
Likes: 0
From: Lake Placid Florida
Racer
Joined: Mar 2014
Posts: 316
Likes: 39
From: Machesney Park IL
Take the air cleaner off and look at the choke plate as you give the throttle a full pump as if you were flooring it. This should close the choke. Then hold the choke plate open and look down the carb throat and pump the throttle again and see if you see a jet of gas squirt into the carb and into the intake manifold. This verifies gas. Then, as someone is cranking it, the choke pull off should open the choke about the gap you could get a dumdum sucker stick into. Without any tools, this would be a quick check for carb related starting.
Instructor
Joined: Jul 2016
Posts: 195
Likes: 37
From: Poway CA
I'm not sure what you mean by no "leakdown". Are you pulling off the airhorn and checking to see if the fuel has emptied out of the bowl overnight? If it has, then you have one of three problems that I am aware of...
1) porous carb bowl which fuel is seeping from (not uncommon)
2) leaking well plugs which need to be epoxied
3) bad fuel pump check valve that can siphon fuel back out of the bowl
If you know there is gas in the bowl and it still is a hard start, check obvious items such as timing, fouled plugs, cracked cap, choke pull-off adjustment (1/4" is close), vacuum leaks, etc.
Please let us know what you find!
1) porous carb bowl which fuel is seeping from (not uncommon)
2) leaking well plugs which need to be epoxied
3) bad fuel pump check valve that can siphon fuel back out of the bowl
If you know there is gas in the bowl and it still is a hard start, check obvious items such as timing, fouled plugs, cracked cap, choke pull-off adjustment (1/4" is close), vacuum leaks, etc.
Please let us know what you find!
Thread Starter
Advanced
Joined: Jun 2015
Posts: 79
Likes: 0
From: Lake Placid Florida
I'm not sure what you mean by no "leakdown". Are you pulling off the airhorn and checking to see if the fuel has emptied out of the bowl overnight? If it has, then you have one of three problems that I am aware of...
1) porous carb bowl which fuel is seeping from (not uncommon)
2) leaking well plugs which need to be epoxied
3) bad fuel pump check valve that can siphon fuel back out of the bowl
If you know there is gas in the bowl and it still is a hard start, check obvious items such as timing, fouled plugs, cracked cap, choke pull-off adjustment (1/4" is close), vacuum leaks, etc.
Please let us know what you find!
1) porous carb bowl which fuel is seeping from (not uncommon)
2) leaking well plugs which need to be epoxied
3) bad fuel pump check valve that can siphon fuel back out of the bowl
If you know there is gas in the bowl and it still is a hard start, check obvious items such as timing, fouled plugs, cracked cap, choke pull-off adjustment (1/4" is close), vacuum leaks, etc.
Please let us know what you find!
I appreciate the Forums help and the wealth of knowledge from its members.
