mercury 1989 90hp dosent run with fuel line conected from fuel pump

[endurance]

198g9 mercur 6 cylinder 90 hp runs when I take fuel line off from fuel pump. When I put it back on. It dies
Can anyone shed light on this. Thanks guys .

 

[Texasmark]

Re: mercury 1989 90hp dosent run with fuel line conected from fuel pump

Do you mean that you remove the fuel line and bypass the fuel pump altogether? Otherwise what do you mean????running off the squeeze bulb?

I had the 115 version of that engine and at WOT is was always thirsty; not that it guzzled gas, quite the contrary, it had a hard time getting gas from the tank to the engine till I replumbed the fuel line, but your problem sounds like something else, like your floats in your carbs (at least one) are not causing your carb's fuel inlet valve to shut off the fuel causing flooding....mal-adjustment or dirty carbs.

Mark

 

[79Merc80]

Re: mercury 1989 90hp dosent run with fuel line conected from fuel pump

Also, you should know that the last year for the 90hp inline 6 was 1985. 1986 the 90hp was an inline 3. With the serial #, there are a few web sites that give that information. One of them is Max rules.

 

[CharlieB]

Re: mercury 1989 90hp dosent run with fuel line conected from fuel pump

Or the fuel pump diaphragm has a hole in it allowing fuel to be sucked thru it into the crankcase of a cyl, causing flooding.

Remove the fuel pump but leave the fuel lines connected, pump the primer bulb abd watch for any fuel leaking from the pump.

 

[endurance]

Re: mercury 1989 90hp dosent run with fuel line conected from fuel pump

Thanks Mark,
I remove the fuel line from the fuel pump
Leading to the carbs. While the motor is running
I catch the fuel with clear water bottle.to see if fuel pump
Is pumping fuel to carbs. Fuel flow from fuel pump Is good
And strong plenty of fuel being pumped to carbs. Problem is when
I re attach fuel line from fuel pump to carbs motor dies.
So when there is no fuel line at all attached to carbs motor runs
When I attach fuel line to carbs. So basically I try to start motor
With fuel line attached and squeezing bulb to prime pump. Will not run
I wait a few seconds remove the fuel line from fuel pump to carbs and the
Motor runs until Fuel in carbs are gone. Can anyone pin point why this is happening
Thanks guys for the help I appreciate it

 

[Texasmark]

Re: mercury 1989 90hp dosent run with fuel line conected from fuel pump

Going to assume that death is due to flooding and if so, you should see raw fuel in the carb(s) venturi rather than a mist of fuel that is normally the case.

You just told me that the carb(s) don't have the capability to shut off fuel and as a result the engine floods, fuel air ratio is severely upset and it dies.

If you know your needle (carb fuel inlet) valve(s) are functioning and you can test that by removing the bowl and one at a time squeeze the bulb and watch the fuel run out of the bottom of the carb then take your finger and lift the float to the proper height (usually right at horizontal or a little higher....don't know the spec for your engine) and when you do the fuel shuts off. If not, replace the needle and seat or if ok, adjust your float to the proper level.

Should fix you right up.

Mark

 

[DavidAK]

Re: mercury 1989 90hp dosent run with fuel line conected from fuel pump

Is the vent open on your fuel tank cap?

 

[endurance]

Re: mercury 1989 90hp dosent run with fuel line conected from fuel pump

Ok Guys ,

Got it all figured out. The ground wire from the power pack
Was loose causing the motor to run on 3 cylinders and flooding the rest.
Which is why when I removed the fuel line it ran because it stopped it from flooding
So I tighten down the ground screw and its running like a champ Hope this helps someone

 

[bamaboi]

Re: mercury 1989 90hp dosent run with fuel line conected from fuel pump

hello my name is joey im new to this site and so far its been a big help well i have always ran Johnson's i just bought a 17ft dixie bandit with a 1986 mercury 90 hp inline 6 well i started by changing the oil in the foot which was black well next i took it to the river and after 20 mins of tryin to start it it started i let it run for 10 mins then cut it off then i tried restarting it and it fired rite up so i took it out it flew i dont have any gauges but again i had a hard time starting it so i read on here that hard starting is a common problem with mercurys so my question is what would i have to do to give it a total tune up i like doing things my self but not opposed to taking it to a pro i live in raleigh nc so does anyone know a pro here if i cant do something i need to do

 

[aussieflash]

Re: mercury 1989 90hp dosent run with fuel line conected from fuel pump

Gday Bam,plenty of ppl here to help you,but you need to start your own thread.
If you have enrichener system, you turn key to on and push in for 5 secs then start with full open throttle(neutral).Good Luck.