stuch

my almost new pum260 will fire and run if i give it full throttle but will not idle for nothing. i swapped out carbs like three times checked for air leaks. the only thing i can think it can be is a timming problem. if is would that be a grey coil problem or the red source coil. i regapped the red coil with a business card still no idle. pulled the jug no scoring clean as a whistle. i put in a new ring thinking bad compression but nope no idle. please help me trouble shoot this issue please. also put in two new ngk plugs.

Dan S

when your Tx and Rx are turned "on" where is the butterfly at?
is the butterfly open?

if you were to apply the brake on your Tx, is the butterfly closing and the most important thing is, if it is closing, how much movement?

it could be not open enough,
adjust your Tx to give more throw to keep the carb open more until you get it to idle.

what carb is it?

Dan.

Dana W

What's your high & low needle setting ?

stuch

644 carb 1 1/2 low 1 1/2 high thats the stock settings. not using the radio. idle stop screw tryed every position. i'am bench starting the motor using my fingers for throttle... i also made sure the pluse hole and gaskets or inline on the carb and the carb manifold. doubled the gaskets between the cylinder and carb manifold thinking i have a warpped manifold. same results. runs strong at the lake not running hot but will not idle...

BMAD01

Take the idle stop screw out, then throw it out! Worthless!![:'(] Set your idle with the radio and all will be well. Brian

MrMikeG

Sounds like an air-leak to me too, did you check between the manifold and head? Are the carb screws too long? If they're too long they go right through the block and hit the head. You could always get a 257!

stuch

tryed a new 257. no the bolts aren't to long.

glennb2006

What sort of revs are you expecting for idle?

Glenn.

PEERPSI

http://www.whobbies.com/big-bore-car...nd-fiction.htm Straight talk on carbs.

http://wem.walbro.com/distributors/s...s/WTseries.pdf From the factory.

If you are having an air leak problem, which is typically what causes idle problems, two gaskets makes no sense. Get the one gasket to work right.

Do you have a water pump? If so what state is the line to the pump from the motor in?

Any change of water in the fuel?

Idle speed should be set around 3500 RPM or 60 hz. An easy way to check the idle speed is to use a volt meter with hz and measure between the kill switch wire and the motor.

stuch

holy crap BATMAN you may just be right. yes i do have a water pump on it and when i was at the lake i noticed every time i went to check the plug there was water in the cylinder. couldn't figure it out for the life of me. i'am going to disconnect the pump and block off the fitting on the carb manifiold. i changed the gas three times.

martno1fan

You kept that one quiet about the water in the fuel sounds like thats your problem ,how did it get in there?.
Mart

BarnacleNZ

maybe a bad diaphragm in the pump??

stuch

no Mart that was the first thing i did was put new gas in it. the motor still will not idle today. i'am baffled. this motor is kicking my azz

martno1fan

Is the carb gasket right way round?sounds daft but it happens,also make sure diaphram is right too.Iv also hjad problems starting a motor when mounts were anodised causing intermitant spark just another idea?.
Mart

stuch

ok heres the low down the jug is a modded one so i said let me see if the motor will run with a stock jug. so i pulled the jug and noticed fuel on the base gasket. i said i bet this jug was machined at the bottom in correctly. put the stock jug on and bingo motor idle at like 1,900rpm and ran like a charm. this jug is going back to the co that modded the engine for me on monday...

MrMikeG

good job!

rcgreenhornet

hey you should never use two gaskett if you have leakes use copper form a gaskett its a spray

stuch

i did use the copper gasket spray on the gasket