Merc 150 Black Max Fuel Problems

[rollo11]

I have a 1985 Merc 150 Black Max that I had mounted on a 1988 Procraft. The mechanic checked compression and ran boat in a test pit, using his gas. Today, I put 7 gallons of mixed gas in tank and pumped it back out ( I am worried about contamination in tank ), then went back and pumped 5 more gallons with oil into tank. I took boat to lake and it started okay, idled okay, and ran about 200 feet before dying. It did this twice before I loaded it back on trailer. Can anyone give me some idea of the possible cause and a fix?

thanks, ron

 

[studlymandingo]

Re: Merc 150 Black Max Fuel Problems

Maybe the fuel pump​

 

[rollo11]

Re: Merc 150 Black Max Fuel Problems

Is there anyway to check fuel pump?

 

[Barnacle_Bill]

Re: Merc 150 Black Max Fuel Problems

When it died did you have to pump the primer bulb back up? The pump itself is very simple. The heart of it is just a flat piece of rubber and they can develope pinholes. If it were mine I would rebuild it. A kit is less than $20 and I would know it was good then.

 

[j_martin]

Re: Merc 150 Black Max Fuel Problems

You're assuming it's fuel. It could something else.

Look at the FAQS and do some troubleshooting on your own. The plus side is youl'll get to know your engine.

hope it helps.
John

 

[fishingdan]

Re: Merc 150 Black Max Fuel Problems

Try it again and inspect the bulb just as it stops. If it is sucked in, then you have a garbage in your tank blocking the fuel pickup or the tank vent is blocked. It, as noted above, you find the bulb has air in it, that means that you have lost prime in the fuel delivery system. This could be any of the following:

- bad bulb
- fuel line from tank to bulb or from bulb to engine is bad and air is getting sucked in
- the fuel line engine connector is bad
- the fuel pump(s) is failing (probably hole in diaghram)
- on engine fuel line bad.

None of the above are expensive or difficult to replace. If it is all 1980's era stuff, I would replace it and be done with it.

 

[rollo11]

Re: Merc 150 Black Max Fuel Problems

Thanks for all your advise. When the motor died, I checked the pump bulb and it was still firm. I put a new pump bulb and line just before taking to the lake, and believe it should be good. Today, I checked the in-line fuel filter and found some white milky substance in it. I will get another one and retry but wonder if this points toward fuel tank issues. Also, there was fuel in filter and fuel pump when i removed it.

I bought this boat without a motor and have no idea how long it had been sitting around. I planned on taking fuel tank out and making sure it was still in good shape, but it appears that ProCraft put the tank on before attaching deck.

Once again, I appreciate everyones assistance.

 

[j_martin]

Re: Merc 150 Black Max Fuel Problems

I fought that white chit for a month last summer.

It appears to be the result of stratification of fuel and alcohol and water. Then bacteria invade and make the white gel.

I drained and cleaned my tank. Then I installed a Racor fuel/water seperator and filter (60 gpm). I threw away the thumb sized filter on the engine.

I also bypassed the aftermarket plastic fuel hose connector someone had installed trying to fix the problem.

I use only non-oxygenated (no alcohol) fuel.

Goes good now.