'76 Merc 85hp not running. Need some pointers.

[pktzygt]

I just bought a boat with this motor. It ran fine with the flushing muffs hooked up, but not in the water. But for $900, I didn't expect much. I have a seloc manual in the mail and I can't get the links to the merc manuals to work. I was hoping for some pointers.

It stalled with throttle. When I squeezed, the primer bulb will keep pumping and not get firm. When primed, it keeps pumping the fuel out of the carb into the airbox.

I figured this could be a stuck float. So I got the parts to rebuild and pulled the carbs off one at a time. The lower carb was clean as a whistle. I cleaned and rebuilt anyway. The idle screw was out 2 1/2 turns.

The upper carb was also recently rebuilt and clean. The gasket was positioned incorrectly and preventing the float from moving. I put it back together, hopefully correctly. The idle screw was out 3 1/2 turns

After reinstalling, both carbs still squirt fuel out of the jet into the airbox. Idle screws are set to 2 1/4 turns from lightly seated. Yesterday afternoon it wouldn't fire at all. I may have just flooded it though. I don't think I messed up the wiring because I didn't disconnect anything.

Any insight would be much appreciated.

 

[CharlieB]

Re: '76 Merc 85hp not running. Need some pointers.

If fuel comes out of the carbs when the primer is squeezed there is still a problem with the float/needle/seat, you will have to look at them again.

Depending on the manufacturer of the carb kit, needles and seats are not the same and shouldl not be switched/mismatched. A solid metal needle requires the red rubber seat be installed. Whereas a viton tipped needle requires that any prior red rubber seat be removed.

You cannot run a metal needle without any seat.

Invert the carb so only the weight of the float holds the needle on its seat and blow into the fuel inlet, can you feel any air movementr, it should not. Lift the float and air moves, let go and it should stop. Adjust final float height and reinstall the carb(s).

Try this link to see if your manual is still available.

http://forums.iboats.com/showthread.php?t=309079&p=2072211#post2072211

 

[pktzygt]

Re: '76 Merc 85hp not running. Need some pointers.

It is a quicksilver brand needle, seat, float, ect. It came with a brass seat and washer, metal needle and I have not found any reference to a rubber seat. Here is a pic that looks just like mine out of the iboats catalog.

Do you adjust float height by bending the metal arm between the needle and the float?

I'll pull my carbs off a bit later. I've gotten quite proficient at it.

Thanks you for your quick reply.