Only if it’s primed

[Old fiddler]

5 hp Briggs, 1302121919 01
Won’t start unless I prime it (w/carb cleaner), hot or cold.
Go cart sat for a year or two.

I cleaned the tank and carb
Rebuilt the carb
Put on a new carb
Put on new magneto (thinking spark was too weak to fire it)
The “upper” tank fuel bowel holds fuel, so it does not drain out
New spark plug

It has about 43lbs compression cold

It runs good, plenty of power, once I get it
started - it will start after 2 or two pulls AFTER priming it.

What am I missing? I am stumped - been fixing these for 60 years off and on, never ran into this

Please help me out here - thank you

 

[slomo]

Go cart sat for a year or two.

Carb is still plugged up or you have a delaminated fuel line or filthy fuel tank. Maybe a clogged fuel filter.

Won’t start unless I prime it (w/carb cleaner), hot or cold.

Choke issue, definitely a lean/lack of fuel issue while starting. Fires off with spray.

Put on a new carb

Chinese Scamazon or OEM? New carb will need testing.

Put on new magneto

Chinese or OEM? New coil will require testing.

The “upper” tank fuel bowel holds fuel, so it does not drain out

If this is a pulsa-jet type, normal ops.

New spark plug

Will require testing. New untested parts means nothing.

It has about 43lbs compression cold

Using a car comp tester? Those read low on small engines. They have a large ID hose for such a small cylinder and a long hose which in this case, doesn't help. Might have a compression release doing its job??

Speculation time about low compression. Could be stuck rings from rust while sitting for 2 years. Carbon fouling ice berg chunks behind the valves holding a valve open. Maybe a valve seat came loose out of the block, again holding a valve open. Having NEVER decarbonized the cylinder/s per everyone's small engine manual. Valves needing adjusted. I would look here as this is an easy check. Not compression related but could have a sheared flywheel key??

 

[slomo]

Make sure the choke is working first.

 

[Rivets]

Compression test shows low, but I never rely on them to make good decisions. Go to your local auto parts store and see if they have a loaner program. Many of the major ones will loan you tools for a deposit and return the deposit when you return the tool. You need a cylinder leak down tester to preform a leak down test on the engine. This will give you a better picture of what is going on with the engine. Two questions I have about your engine. Did you purchase the new carb from AutoScam, FleaBay or an original OEM carb from a known good dealer? The techs on this site have found that those purchased aftermarket have a 50+% of being faulty. What was the part number of the carb you purchased? OEM part number should be 299437.
To Slomo, why don’t you look up the engine before asking question? You would have seen it is a pulsajet carb with no fuel filter because it is tank mounted.

 

[Old fiddler]

Make sure the choke is working first.

It’s a manual rotary choke, it is working - it acts the same with 2 different carbs

 

[Old fiddler]

Carb is still plugged up or you have a delaminated fuel line or filthy fuel tank. Maybe a clogged fuel filter.

Choke issue, definitely a lean/lack of fuel issue while starting. Fires off with spray.

Chinese Scamazon or OEM? New carb will need testing.

Chinese or OEM? New coil will require testing.

If this is a pulsa-jet type, normal ops.

Will require testing. New untested parts means nothing.

Using a car comp tester? Those read low on small engines. They have a large ID hose for such a small cylinder and a long hose which in this case, doesn't help. Might have a compression release doing its job??

Speculation time about low compression. Could be stuck rings from rust while sitting for 2 years. Carbon fouling ice berg chunks behind the valves holding a valve open. Maybe a valve seat came loose out of the block, again holding a valve open. Having NEVER decarbonized the cylinder/s per everyone's small engine manual. Valves needing adjusted. I would look here as this is an easy check. Not compression related but could have a sheared flywheel key??

Yes, car comp. Tester, it has not sheared the key. I will start over again with suggestions thank you

 

[StarTech]

Have you check the valve clearances. I know old L-heads are hard to start when the valve clearances approach zero.

 

[Fish]

Take off the air cleaner and snap a few pics, it would give us more info. One shot with the choke open, and the other closed.

 

[Old fiddler]

Take off the air cleaner and snap a few pics, it would give us more info. One shot with the choke open, and the other closed.

I will have to do it later, if I can figure out how to do it

 

[Old fiddler]

2 of new carb on motor
2 of old carb I am holding
Both acted the same -