Needle valve will not close??

[al windybank]

I have an early 80s (I think) mariner 50hp 4 cyl. It has two carbs. The top carb squirts fuel out when you pump the priming bulb. I have rebuilt the carb but: it was totally clean inside, the float floats and is free to move, the needle valve was/is clean and doesn't look worn. When I blow through the fuel pipe and move the float up it shuts off ok. However, when I fit it to the engine fuel still squirts out of the vent in the front of the carb when I pump the bulb.<br /><br />What am I doing wrong? Any help appreciated.

 

[12Footer]

Re: Needle valve will not close??

Mariner 50 has an idle mixture screw in a hole just above the throat in the front...I think.<br />Make sure this idle mixture screw is still there, and adjusted 1.25 turns out before running adjustment. If it's missing, this is your poroblem. Also, check the carb mounting gasket,as it can be accidentally reversed (has a small hole thru it from flange-to-carb body).<br />If it is reversed,it plugs that small hole,and no go.<br />Good luck.

 

[al windybank]

Re: Needle valve will not close??

Thanks for the help. I think that the idle mixture screw is in. I have attached a picture of where the fuel squirts out from. I think that it is the bowl vent. It is not marked in my manual.<br />

 

[alcan]

Re: Needle valve will not close??

Hi Windy<br />It sounds to me like the float needs adjusting. If your manual is unclear on this procedure, I will try to send you some pics. I will need your e-mail address.

 

[al windybank]

Re: Needle valve will not close??

Thanks for the offer. My email address is awindybank@cirruscor.com. My manual has similar carbs in but not my exact one. The adjustment instructions are vague to say the least. So far I have tried what I know without any luck. Any information that you can give me will be gratefully received.<br /><br />Thanks

 

[alcan]

Re: Needle valve will not close??

Hi Windy<br /> Your are correct, that arrow is the bowl vent. You should have that info in your e-mail.

 

[Boatist]

Re: Needle valve will not close??

Make sure the floats and is not binding on sides when installed. Make sure it is set at right level. If any question bend the tab a little to set fuel a little lower. Last change needle and seat even if look ok.

 

[al windybank]

Re: Needle valve will not close??

Thanks for the help. I'll be working on the engine this weekend and I'll let you know how I get on.