Crankcase full of gas??

[surfjunkie]

What would cause an engine to fill up with gas to the point of spraying out the spark plug holes like a water logged engine.

Quick history. In laws b2. Ran fine but I noticed gas leaking from carbs (diaphragm side) so i pulled carbs and replaced with different set. Tried to start and starter would spin and stop. Pulled plugs and what appears to be gas (appears to be no water) is shooting out the plug holes.

Stuck open needle and seat?

 

[special fx]

N&S

 

[surfjunkie]

N&S

By the 2nd or 3rd attempt to start it was stopping the starter hydro lock style. Happen that quick?

 

[tor*p*do]

yup

 

[Big Kahuna]

Been sitting a while? Need stuck causing fuel to free flow. Pressure in the tank can cause the fuel to pump.

 

[surfjunkie]

Been sitting a while? Need stuck causing fuel to free flow. Pressure in the tank can cause the fuel to pump.

Carbs had been on the shelf for a while. I did push the needle arm several times just to make sure they were moving free. And they seemed to be. ??

 

[keith t]

Needles n seats, need to check pop offs are holding tight at correct pressure

 

[Kny21]

Could be sticking open or the needle tip is bad and not seating, whichever it is you replace both n/s together. While you are at it I'd order a new tank valve too. Small chance it could not be venting and that is popping a good n/s.

 

[Gliderskier]

If carbs check out good. Do you hae a primer. My plunger went bad once and when the tank would get pressurized fuel would go straight through the primer line and down the carb.

 

[speedysprocket]

Could be sticking open or the needle tip is bad and not seating, whichever it is you replace both n/s together. While you are at it I'd order a new tank valve too. Small chance it could not be venting and that is popping a good n/s.

Seats do not need to be changed with the needles. The needle is rubber- it's not wearing the brass seat out... If the seat is corroded or otherwise damaged, then yes, it should be replaced. But it is not matched to the needle.

 

[surfjunkie]

No primer. It has to be related to the replacement carbs cause it was running fine the day before. I'm just really surprised how much gas got in there so fast. The needle opening isn't that big even if both were stuck wide open. Thanks for responses.

 

[JetManiac]

Seats do not need to be changed with the needles. The needle is rubber- it's not wearing the brass seat out... If the seat is corroded or otherwise damaged, then yes, it should be replaced. But it is not matched to the needle.

N&S always come as a set, why wouldn't you always replace both?

 

[speedysprocket]

N&S always come as a set, why wouldn't you always replace both?

If the seat is the right size, there's no need to get a new one because the needle wore out.

 

[JetManiac]

If the seat is the right size, there's no need to get a new one because the needle wore out.

You can't buy just a oem mikuni needle separately as far as I know.

 

[Wizards Powersports]

You can't buy just a oem mikuni needle separately as far as I know.

Righto, only come as pairs from Mikuni.


Sent from my iPhone using Tapatalk

 

[speedysprocket]

You can't buy just a oem mikuni needle separately as far as I know.

Sorry, thought the Mikuni rebuild kits had needles in them.

 

[JetManiac]

Sorry, thought the Mikuni rebuild kits had needles in them.

No N&S with mikuni rebuild kits, maybe you were thinking of keihin kits which include a needle?

 

[speedysprocket]

Ok my bad.

 

[Matt_E]

Seats do not need to be changed with the needles. The needle is rubber- it's not wearing the brass seat out... If the seat is corroded or otherwise damaged, then yes, it should be replaced. But it is not matched to the needle.

Can't really buy just needles. I used to replace them in sets for that reason.

 

[john zigler]

I have seen bad fuel pump diaphragms, allowing fuel into crank case through the pulse line. In short, go though the carbs completely.

Seats can and DO wear out. They are brass, and wear towards the top, allowing the needle to "bind" and not sit properly.