mercury200 black max

[dcfrank3]

there are six, what appears to be vacuum lines connected to fittings on the block just behind the carb area. One of these on the driver side, bottom is leaking quit a bit of fuel while idleing. It seems to be under compression or mixed with air as it leaks. The leak is between the block and the fitting. Its very tight, but leaks alot. Are these fittings screwed in or pressed in? What are their purpose? Is fuel suppose to be there? Help. They look fragile, not sure how to stop leak.

 

[Coolmaker]

Re: mercury200 black max

Those are "bleed off lines", replace the hoses, and all should be okay.

 

[heybaylor]

Re: mercury200 black max

they are brass checkvalves...they have a one-way ball seal , and they screw in .<br />the purpose of them is to let the intake port pull the "puddled gas in the reed manifold to the cylinder to burn. this occurs at idle <br />keeps from sucking the "puddle" in when you roll on throttle..results in cleaner low speed operation.<br /><br />they should all be checked. you should be able to pull air out from them , but not push it back..<br />use a long clean hose and test (gas taste's terrible) , best to use a baby syringe....lol<br />make sure the hoses are in good shape all the way to the cylinder barb..no kinks/no leaks

 

[dcfrank3]

Re: mercury200 black max

Thanks, the check valve is leaking between it and where it seats. Its spurting gas at idle. Now that I know it screws in, I can unscrew it and see if there is a defect. It is so tight Im afraid it will twist off. There must be something clogged to backpressure a leak here?

 

[heybaylor]

Re: mercury200 black max

nah , it only has very little pressure.."piston displacement" only..<br />If it it leaking as you say , it is "cracked"..<br />it "seats " only by the threads..

 

[dcfrank3]

Re: mercury200 black max

heybylor, thanks, I went to unscrew it and it kept turning but wouldnt back out, so I pulled on it and it came out. Guess this 1988 model has some pressed in. But you could see where the brass was seated on 2/3 of the round but not in one place. Checked the valve flow and worked as if okay as you explained, so I used a tiny bit of black all purpose engine-build RTV sealant and re-seated the valve with a small deep-well socket. Anxious to see if corrected. Learned alot, Thank you and all for responding. MY SELOC engine book does not describe the purpose or checking of these valves.

 

[ronmold]

Re: mercury200 black max

RTV isn't real good when in constant contact w/gas. You might try some Marine-tex epoxy or JB weld after cleaning with a good solvent.

 

[heybaylor]

Re: mercury200 black max

ask a dealer to look up part number and see if it<br />has threads. either way, threads or no threads I would replace that valve .