Flat primer ball at full throttle

[Delta22710]

Im getting a flat primer ball at full throttle. Coasting speed I'm fine, when I open it up, bogs down and stalls. Ball flat like a pancake.

New plugs, new primer ball, new fuel lines, carberator clean, anti siphon good, vents good, tank clean, tank filter clear, fuel pump screen clear. I find no restrictions. What else should I be checking.

Also before it gets asked, compression is fine in all 3 cyl, and the carb screws are all lightly seating and a full turn out.

85 hp force outboard, 1984

 

[Frank Acampora]

Re: Flat primer ball at full throttle

The ONLY reason a primer ball goes flat at any speed is because the fuel pump is drawing more fuel than the fuel system up to the outlet end of the primer ball can deliver. THUS: you need to rechek the outlet check valve on the primer, and the line back to the tank. If you have a quick-connect at the tank, check the fittings, especially the male. Junk can get packed in behind the check ball. Try running without the quick-connects and see if that solves the problem. If so, a trip to your local Wal Mart for Mercury quick-connect fittings will be well worth it. The fuel passages are much larger than Chrysler/Force

 

[robert graham]

Re: Flat primer ball at full throttle

Are "new fuel lines" the correct inside diameter to allow for sufficient flow at full throttle? Inside of fuel lines from primer bulb to the tank are clean and clear? Check valves in "new primer bulb" working freely? Did you use Teflon Pipe Tape to assemble any of your fuel fittings?...these can create thin teflon ribbons that can easily plug a fuel line or fitting. It's a good bet there's a restriction between the tank and the motor.

 

[Delta22710]

Re: Flat primer ball at full throttle

Checked the male fittings, all clear. The last fittings were not quick connect and it did the same as it does with the quick connect.
Primer ball is brand new, I doubt it's a faulty one since its found the same "sucking flat" and the one we just replaced. And no Teflon tape was used at all

 

[duke33]

Re: Flat primer ball at full throttle

I'm thinking the tanks not venting properly....

 

[Delta22710]

Re: Flat primer ball at full throttle

Good call, I'll go out now and try running with the gas cap off.
What sucks even more is I am on vacation..... Lol. I'll repost my results.

 

[Delta22710]

Re: Flat primer ball at full throttle

Just got back. Started fine, idles fine, took the gas cap off for ventilation. Started out slow, great, then medium great, then wide open ran for 2 minutes and then the ball sucked flat.... Crap!!

 

[duke33]

Re: Flat primer ball at full throttle

Check the threads out at the bottom of this page. Similar stuff. I hope they help.

 

[LAndrus]

Re: Flat primer ball at full throttle

Had a similar issue after I rebuilt my fuel pump......stupid me, I had the lines backward. Try switching where the lines are on the fuel pump and see if that fixes the problem.

 

[Delta22710]

Re: Flat primer ball at full throttle

Any other advice before I bring it to the shop?

 

[foodfisher]

Re: Flat primer ball at full throttle

Debris clogging the pickup tube in the tank.

 

[Delta22710]

Re: Flat primer ball at full throttle

From tank to fuel filter is clear. Fuel filter screen is also clear

 

[pnwboat]

Re: Flat primer ball at full throttle

The only thing that will cause your symptoms is a restriction at or before the primer bulb like Frank A mentioned in post #2, or you have a fuel pump that is powerful enough to suck the chrome off your bumper. What size fuel lines do you have?

 

[emoney]

Re: Flat primer ball at full throttle

Have you tried running it on a different gas tank with a different fuel line? I'd start there and if it ran fine, then I'd try it with a new tank but the old fuel line/bulb until I narrowed it down. Nothing against going to a shop with it, but it can get expensive having someone fix a problem, let alone track it down.

 

[Delta22710]

Re: Flat primer ball at full throttle

Good idea, I'll try running it from a different gas tank and see what happens

 

[Delta22710]

Re: Flat primer ball at full throttle

Nope, same thing.... Crap!!

 

[pnwboat]

Re: Flat primer ball at full throttle

Make sure the primer ball is installed correctly. Arrows should point towards the motor. If that's OK, bypass the primer ball and try it without it.