Predator 212 (hemi) problem

[john__n]

Hey all! New to the forum but hopefully you guys can help!

I have a new 212 which I removed the governor completely, unplugged the low oil sensor (did not remove innards though), added an exhaust, new air filter, and stage 1 kit jets. Runs very nicely upon start up and will run for about a minute at full throttle.

Problem is it dies after about a minute and when it dies it take about 10 pulls to get enough fuel back in to get it going again. If I manually shut it off I can fire it right back up with one pull.

I put a known working carb on it to see if I could isolate the problem in the carb but the new carb does the same thing.

I put a know working pulse pump on it to see if I had a bad pump... same issue.

Spark plug looks good, not running lean or rich.

From what I could tell the magneto looks good.

I'm beating my head against the wall trying to figure this out. Hopefully someone has experienced this and can point me in the right direction.

Thanks!

 

[Brianator]

Sounds like maybe the fuel bowl is going dry? Check for good flow on the fuel feed to the carb before anything. A pinched/kinked line could restrict it. Vapor lock is another possibility, if the fuel is getting superheated inside the line and turning to vapor that can cause what you describe. Tinfoil crinkled around the line is a good insulator for stuff like that. Based in the info you've given I cant think of anything else that could cause it unless those carbs just cannot keep up with the demand.

 

[john__n]

Sounds like maybe the fuel bowl is going dry? Check for good flow on the fuel feed to the carb before anything. A pinched/kinked line could restrict it. Vapor lock is another possibility, if the fuel is getting superheated inside the line and turning to vapor that can cause what you describe. Tinfoil crinkled around the line is a good insulator for stuff like that. Based in the info you've given I cant think of anything else that could cause it unless those carbs just cannot keep up with the demand.

I checked all the lines and they are free flowing. Haven't thought about vapor locking so I'll do some research on that ans see if the symptoms line up. Thank you!

 

[Karts of Kaos]

what about the vacuum relief on the gas tank?

 

[Brianator]

what about the vacuum relief on the gas tank?

That's an excellent point! Very quick and easy to test too!

 

[mckutzy]

What does the plug look like??
Let's see some pics of the carb setup??
Is the tank not attached to the engine??
You mentioned pump, is this in a kart??