merc 85hp Fuel Delivery Issue, Seemingly?

b0b88

Cadet
Joined
Jul 30, 2008
Messages
11
I am really new to boating and engine problems, when i read a post earlier someone said that they pumped the primer bulb up tight?? what does that mean??? when you first start the engine to you prime the bulb until you cant squeeze it anymore??

The reason i ask this is because i bought a boat with the outboard engine in question and when i took it to the river recently the engine started up just fine. but when i went to accelerate the engine would accelerate quikly and then die out. and it seemed the only way to get the engine started again (after quite a but of trial and error) was to pump the primer bulb again?? really confusing to me? I figure its something to do with the fuel pump or fuel filter im hoping anyway. or even better maybe i didnt prime the fuel thing correctly that would be even better. but i doubt thats the problem because i couldnt be so lucky.

p.s. the boat reved up fine with the muffs on? could it be the load on the engine pulling it down?? and the engine is an inline 4 and the lower end of the unit has not been serviced in some time. i'm planning on learning how to do it myself. I'm going to order a new impeller from maxrules.com and possibly a fuel pump rebuild kit. but what confuses me is that there is no motor in the fuel pump rebuild kit? is there not a motor that delivers fuel to the engine?
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,099
Re: merc 85hp Fuel Delivery Issue, Seemingly?

Bob, It does sound like the fuel pump is bad on that motor. BTW - Some of the 85HP motors had two fuel pumps. You need to determine which model of fuel pump repair kit you need. You may look up serial number of the motor on maxrules.com web site to get the year. Now look up the exploded parts list on crowleymarine.com, by year.

The fuel pump is a diaghram plus two check valves and some gaskets, mounted in a simple aluminum casting. As the pistons move up and down, pressure and vacuum travel thru hoses from the crankcase to the fuel pump. The alternate pulses cause the diaghram to move in and out, and in combination with the check valves, pump fuel to the carbs.
 

b0b88

Cadet
Joined
Jul 30, 2008
Messages
11
Re: merc 85hp Fuel Delivery Issue, Seemingly?

Thank You very much! my boat is at the river at my sisters house (convenient storage) :D so i will have to get my brother in law to find the exact serial,

Thanks a Million! i will keep you updated!
 
Top