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my 1987 force 85 hp kills whenever i give it gas

mbeavy

New member
hi. I recently bought a boat with a 1987 85 hp motor. It had run fine until recently. I keep it at a slip at a marina and we had a few rainy days, and I hadn't gotten there to bilge it out. When I finally did there was about a foot of water in the boat. I pumped it out and when I started the motor, it started fine but when I hit the throttle it died. Over and over again. It sounds like its gonna go, it;ll lunge a few feet, then die. I thought maybe some water had gotten into my gas( it has a built in gas tank and the cover is on top in the back of the boat) so I added 5 gallons of new gas with a can of seafoam to see if that was it but it does the same thing. sure sounds like it wants to go, but just won't. I'm a novice to boat repair, but it seems like a simple thing. Any ideas?
 
First off just adding gas to a tank with water is just compounding the problem.
The Seafoam doesn't do anything, it's WAY over rated.
IF?? water got in? then you'll probably need to drain the tank.

Unhook the fuel line at the intake side of the pump.
Then squeeze the ball into a glass jar and see if there's any water in there??
Then if there's water? drain the tank.

Tilt the front of the boat up.
The gas line can be used to siphon off the fuel.
When it's empty, remove the fuel tank sending unit.
Then stuff "GOOD" paper towels into the tank and soak up the left over water.
Count the towels and make sure you take out as many as you put in.
Cheapo towels can shred and stay in the tank.

The tank is a sealed unit and shouldn't let water in.
If it did?? then figure out where it came in?? usually the tank sending unit hole?
Install a water/fuel separating filter, between the tank and the motor.
Then add a Fram filter G2 / G3 or G12 between the carb and the pump.
This stops the tiny particles from entering the carbs.

IF? there's no water?
Then check the carbs for dirt in the bowls.
 
thanks for the info jerry, turns out i was wrong and there was no water in my tank(i really never thought there was but it kinda seemed like it the way it was responding)the problem i believe is i'm not getting gas to the motor. it starts fine but just burns off the gas i choked it with, it won't continue to run in neutral. i'm a novice boater, but i'm guessing the problem is prolly the fuel pump. any way to zero in on a gas flow problem?
 
so, I took the fuel pump off, but like I said, this is all new to me, what am I looking for? All the gaskets seem to be intact. The diaphragm looks a little worn, but no tears. Do I just buy a re-build kit?
 
No tears but is it flat or streched out?
Replace as it's out already.
When back together, test it for flow.
Get a piece of hose 1/4" x 12"and a glass jar.
Take the hose from the pump to the carb off, then install the new hose.
Then turn the motor over and see how much fuel comes from the pump.
This will tell you if the valves are working in the pump.
It's a low pressure pump 1-2# so don't expect a lot of fuel.

But no tears means it's probably not the pump.


Check the linkage? see if the plastic connectors are ok?



Does it rev up but not move?
Possible spun hub?
 
I replaced the diaphragm and put in new gaskets, put it all back together and that was it, it started running great again. thank you for the help
 
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