Fuel problems Merc 898

[guypreston]

I just purchased a 1979 Wellcraft Airslot with a Merc I/O 898, it had been sitting for over a year so i removed all the old fuel from the tank and cleaned the fuel lines and replaced the fuel/water separator. I removed and cleaned the fuel pump of which was really hard to get back on ( any tricks to that ? ) and blew fuel through the system to prime before starting.
I fired it up but it died soon after, i then removed the line from the pump to the carb and turned it over no fuel. Either it is the pump or the rod that rotates and makes the pump, pump is not working. If it is just the pump no worries i can replace that but what if it is the rod from the engine that is not making the pump work ?

Any help would be great
Cheers.

 

[Bondo]

Re: Fuel problems Merc 898

Ayuh,.....

On a SBC, the fuel pump push rod rides on the cam, thru the block, to move the pump lever....
Did you get the fuelpump pushrod into it's hole,+ keep it in place when you reinstalled the fuelpump,..??

 

[MikDee]

Re: Fuel problems Merc 898

I had 2 Wellcraft Airslots 18.5', a 1971, and a 72, one with a Merc. 165hp straight 6, and one with a Merc. 188hp (888) 302V8 (Ford), and both had flat saddle type fuel tanks on each side of the boat, the later one had them mounted a bit further aft, But, the point I'm trying to make is I had trouble with the fuel strainer, which is inside the 3/8ths" aluminum fuel line on each tank, it is a piece of mesh screen that slips into the fuel line, shaped like a small mascara pencil, and all were full of debri! I decided to remove them completely, and do my filtering at the motor only, because they were such a hassle to deal with. I don't know how your later model boat is made, if it's the same or not, but maybe this is your problem? Let me know what you find?

 

[Don S]

Re: Fuel problems Merc 898

Hook up an outboard tank to your fuel pump, and pump the fuel bulb to prime the pump and carb. Then see if it will start and keep running on it's own.
If it does, you have a problem in the fuel suppy system

 

[guypreston]

Re: Fuel problems Merc 898

Bond-o

I was not able to get the push rod back up into its hole, i also took video of the push rod as i turned it over and it did not move, can i force the rod back into position or will the motor have to be dismantled ?
okay i managed to push the rod back up into the engine block reinstalled the fuel pump still no fuel to the carb, i am pretty sure the push rod is not moving

 

[MikDee]

Re: Fuel problems Merc 898

Bond-o

I was not able to get the push rod back up into its hole, i also took video of the push rod as i turned it over and it did not move, can i force the rod back into position or will the motor have to be dismantled ?

I don't get it? Is the push rod in place? If so just grab it with (a pair of pliers with some tape on it's jaws, so you don't damage it,) or anything handy, and push it back up into the hole, then put your fuel pump arm in there to hold it up, then just bolt the fuel pump on,,, is that so hard!

If need be there is usually a plug at the bottom of the fuel pump mounting plate you can take out to get the rod out, or use a tool to push the rod back up into the hole Then put your fuel pump arm in to hold it, then put the plug back.

 

[guypreston]

Re: Fuel problems Merc 898

I was eventually able to get the push rod back up into its hole with alot of force, i mounted the fuel pump and still no fuel to the carb, im pretty sure the rod is not being pushed

 

[Don S]

Re: Fuel problems Merc 898

That rod should slide back and forth effortlessly, if you had to force it, there is a serious problem.

 

[Don S]

Re: Fuel problems Merc 898

What you are going to have to do is remove the fuel pump. Remove the cover on the block that is held with 2 bolts. Remove the push rod completely and find out why it's so hard to move.

 

[guypreston]

Re: Fuel problems Merc 898

so i should be able to just pull the rod out of the block right ? anything to watch for oil etc ?

 

[WizeOne]

Re: Fuel problems Merc 898

No need for screaming with bold print GP. We hear you loud and clear.

 

[MikDee]

Re: Fuel problems Merc 898

What you are going to have to do is remove the fuel pump. Remove the cover on the block that is held with 2 bolts. Remove the push rod completely and find out why it's so hard to move.

Don has it right, the push rod is supposed to slide easily on a layer of oil, if you bent it, you'll need to replace it. It rides on, & is operated by a camshaft lobe. You will not lose any oil taking it out, and when you replace it, put a light layer of grease, or vaseline, on it to hold it in place so it doesn't slip down, when putting your fuel pump back on.

 

[guypreston]

Re: Fuel problems Merc 898

okay, the push rod is stuck fast there is no way i can pull it out

 

[MikDee]

Re: Fuel problems Merc 898

Well, you hafta replace it now, if you have the fuel pump face plate off, you should be able to grab it with a vise grips, wiggle it some, and pull it out, or tap the vice grips with a light hammer as you're doing this, to pull it out.

 

[guypreston]

Re: Fuel problems Merc 898

still no go i have hammered wiggled and pulled as best i can it wont budge,
when i hammer it in and turn the motor it dose push it out some but thats as far as i can get it to go,

 

[guypreston]

Re: Fuel problems Merc 898

Okay i got it out, i have a replacement arriving tomorrow and i will try again,

 

[guypreston]

Re: Fuel problems Merc 898

Boat is now running great, Thanks to all that helped with answers to my question's really appreciate it.
Summary....

First check that fuel is getting to the carb, if you remove the line from the carb to the fuel pump and there is no gas coming through as you crank the engine then work your way back through the system. Check the Carb, fuel lines to the carb,fuel pump, fuel filter, lines to gas tank, valve on gas tank.

It will all come down to a process of elimination.

Cheers,

 

[Coors]

Re: Fuel problems Merc 898

If you look close at the front of the engine, there is a 3/8" bolt (not the head size), that lines up with the fuel pump rod.
Temporary install a longer bolt-it will hit the rod, and hold it up, good to be on the heel of the cam lobe when this is done). Remember, when installing original bolt back in, it needs some sealer, as it goes into internal oil splashing.

 

[MikDee]

Re: Fuel problems Merc 898

If you look close at the front of the engine, there is a 3/8" bolt (not the head size), that lines up with the fuel pump rod.
Temporary install a longer bolt-it will hit the rod, and hold it up, good to be on the heel of the cam lobe when this is done). Remember, when installing original bolt back in, it needs some sealer, as it goes into internal oil splashing.

That's what I meant previously, not a plug, a bolt,,, I bet he had to do this to get the rod out.

 

[Coors]

Re: Fuel problems Merc 898

nah, factory bolt holds on a bracket, it is about 3/4" long, takes a 1 and 3/4" bolt to push the rod tight. Old GM mech trick.