85 Force 85hp starts, but will not stay running

[ToonTy]

Hello Everyone,
I have an 85 Force 85hp that I pulled off an old boat and put on my pontoon. The compression was checked at purchase this spring and it was good. I had it out and it started really hard and seemed to lose power at times after running it 3/4 throttle. I replaced all fuel lines, put a new diaphram (old one did have a split in it) in the fuel pump, replaced spark plugs, and cleaned/rebuilt the carbs. When I hooked it up to muffs to adjust the carbs the motor fires right up, but after 20-30 seconds it dies. I can keep it running a little longer if I put it on fast idle, but it eventually dies again. Every single time it fires right back up, but I am at a loss as to why it won't stay running. I have adjusted the idle needle between 1 turn out and 1-1/2 turns out and the same thing happens.

 

[jerryjerry05]

The air screw needs to be at 1 turn out and left there.

It sounds like the fuel delivery is the problem.
Ethanol melts the inside of the older hoses, maybe the hose is collapsing and shutting off the fuel?

Tank vent could be clogged with bugs? Small wasps get in the hose and build nests, shutting off the air.

You test the overheat system?
Possible it's getting hot??
Key on, ground the orange lead at the buss bar.
The alarm should sound.

Check the squeeze ball, the one way valve might be defective???

 

[spserg]

Last summer when I purchased my 85, I went through all the normal maintenance before launching. Once I did, it ran great for a few mins and then died. Since we were fishing, I pulled the cowl and did a minor tweak to the carb. Started up again, ran for a few and then died again. Anything below 1/2 throttle and it would die. After scratching my head over and over, I found that the exhaust bellow from the motor to the outside case had a large tear. Essentially, every time I ran it the exhaust would fill the cowl and choke it out. I would pull the cover and it would start right up again. It might sound obvious, but its worth taking a look.

 

[ToonTy]

Thanks for the responses.

I have changed all of the fuel lines. I am trying to run the motor with muffs on and the cowl off, so not an exhaust issue. It runs great for 20-30 seconds and then dies. I hit the key again and it fires right up for another 20-30 seconds. I checked the fuel line bulb and it is fine, no leaks. Motor is not overheating.

When I pull the plugs after it dies they have a little fuel on them. Is it a possibility that I am still running too rich with the idle needle set at 1 turn out?

 

[Nordin]

It should run at 1 turn out, do not set it leaner then 3/4 turn (I never set it leaner then 1 turn out).

If you push the choke when it want to dies, does it then stay runing for some 10 seconds?
If it does then it is a fuel issue.
Clean the carbs again if you have done it before, the fuel inlet valves may stick in close position.

When it dies, is the primer bulb soft, firm or stiff?
If the fuel pump and the check valves in the fuel line and primer bulb is okey the bulb should be a little soft, not stiff.

If you have not put a inline fuel filter (FRAME G2 or equal) between the fuel pump outlet and the carbs, do it!
Then you can easy check that fuel is delivered as is should.

 

[jerryjerry05]

Squeezie, going bad, not leaking but shutting the fuel off.
You can try running it on a second tank?

You test the overheat alarm?

Fuel on the plugs, normal.

The floats might need resetting?

Do you have to squeeze the ball to get it restarted?

 

[ToonTy]

I plan to try to run it on a second tank tonight.

I do not have to squeeze the ball/bulb to restart and it starts up each time no problem. Bulb is not hard after running.

I have a fuel filter before the fuel pump and I cleaned the screen when I replaced the diaphram on the pump.

If I choke it while running it kills it quicker. That is why I feel like I may be getting too much fuel.

When I cleaned/rebuilt the carbs the floats all checked out with no leaks and the adjustment with the float and needle were as described in the manual (parallel to the body of the carb when shut).

 

[jerryjerry05]

The squeezie's only job is to draw fuel from the tank.
It gets hard when the bowls are full(if the needle/seat is working right).
Then it just sets there.
It shouldn't stay hard but shouldn't collapse either.
The one way valve can stop the fuel from being drawn by the fuel pump.

Sometimes if the filter is before the pump and not after it can make the draw too hard and
fuel won't flow enough to keep running.
You have a water separating filter in the system?
Usually they're before the pump.
That might be dirty and causing problems.

Prime the system, get it ready to run.
Unhook the fuel line to the carbs and put in a glass jar.
Start the motor and check the fuel flow.

You test the overheat alarm?

Install a spark tester and run the motor as you watch it till it dies.
See if the spark goes away as it starts to fail??

 

[ToonTy]

Tried a different gas tank with new line with different bulb/ball and no change. Tried to put the fuel filter (typical sediment filter) after the fuel pump instead of before and no change. Tried to unhook the tachometer because I heard if that isn't working properly it can damage the electrical system on the motor and no change.

I tried to view an in-line spark tester on each cylinder while it was running. It seemed to have weak spark on the middle and bottom cylinder when it started to sputter and die. Thoughts?

 

[Nordin]

Is it spitting fuel out of the carbs?

I would suggest you to clean the carbs once again, set the floats parallel with the carb bowle edge when turned upside down.
Set the air fuel mixture screws 1-1 1/4 out from seated.
As you have the carbs off check the reeds by looking into the crank case, no reed pedal should be bent or broken.

 

[jerryjerry05]

You can try swapping the packs around.??
Might help, might not.
The weak spark as it dies, could be the stator, or the regulator?
You have the original regulator?

Test all connections and grounds.


outboardignitiondotcom has test procedures for the electrical system.

 

[ToonTy]

Went to Ouboardignition.com and tested the stator and trigger, all good. I tested the rectifier and it is only giving me 400,000 to 550,000 ohms when I connect my meter as described. They say is should be over 1 M ohm, so I assume that is over 1,000,000. Do you think this could be causing my running problems? Seems odd still that it starts and doesn't stay running.

 

[ToonTy]

Can't get a new rectifier until early next week, so I went to O'Rielly's to get a compression tester just to check it out again...

Cold I was at 135 psi on all 3 cylinders. After trying to warm the engine some with the start and run for 30 seconds or so a few times I checked again. When the engine was "warm" I got 130 psi on all cylinders. My manual calls for 145-165 psi, do you think I have a compression issue? If so, what? Rings? Gasket?

 

[jerryjerry05]

If all are 135# then I'd guess the gauge is the problem.
They don't have real good equipment to loan.
Harbor Freight is JUNK too.
These 3 cyl. motors, if the comp is low on one cyl. it can make the motor turn over
REAL SLOW or not at all.
Yours runs, I'd bet there is no comp trouble.

The difference in hot or cold when doing a comp test??
Never saw a difference.
Having the throttle open all the way: again never saw a difference.

 

[ToonTy]

Still waiting on the new rectifier, should be here tomorrow or Thursday. Talked with several marine mechanics and they all seem to be baffled. I was told to turn out my idle needs to 2-1/2 turns and see if it would run (and if it does how it runs). I plan to try the rectifier and then if no luck give that a go.

 

[jerryjerry05]

The air screw: Factory says 1 turn out and leave it.
1985 85hp.
Wouldn't run right, idled bad.
Ended up turning out the needles almost 3 turns before it ran right.
Set them and they ran like that for years????

 

[ToonTy]

New rectifier and no success, but at least I know my charging system is getting the correct voltage now. The old rectifier was still giving some odd readings.

I tried turning the idle needle out to 2, 2-1/2, and 3 with still no success. I even tried to take the old inline filter off and replace it with a new one that can handle larger volume (3/8" inlet/outlet). It still started and ran for the first 20-30 seconds.

Is it possible that my fuel pump has a faulty fuel pump valve? When I look online it says that I need to order 3. Are there three in there? Are they hard to change/test?

I am sorry. I am truly frustrated here. I know I have spark, compression, and fuel at start. What in the world is making it die after a few seconds of running? Why would it start right back up again? It does backfire occasionally on starting, but then starts after a I hit the ignition a time or two again.

 

[jerryjerry05]

In 35 years I've seen only one bad valve in the Force/Chrysler fuel pump.
I removed the pump, disassembled and the valve came out in pieces.
The crazy part was I wasn't having a problem, just changing the diaphragm SOP.

 

[Zink357]

You mentioned it has weak spark as it starts to sputter and die... Did you try what Jerry said "The weak spark as it dies, could be the stator, or the regulator?" Did you test the regulator or stator?

To me it still sounds fuel related. Put a clear fuel filter or fuel line somewhere before the carbs and start the engine and see if the fuel flow gets cut down/off before it dies.

Can you keep the engine running by squeezing the bulb continuously while running? Or when it dies can you drain the bowl and see if there is still gas in it. I'm wondering if it burns all the gas in the bowl and then dies. Probably not since you say it fires right back up again without priming.

Will it stay running if you open the throttle up some instead of just idling?

 

[Zink357]

Seen this on another forum, not sure if it will help but it is for a different brand motor so color wires maybe different...

"Disconnect the black/yellow wire from the powerpack. With engine NOT running but key in ON position. Check to see if there's any voltage being applied to that black/yellow wire.

Even a microvolt is enough to damage the powerpack.

If no voltage is present, leave that wire disconnected and try the engine again. If the problem ceases to exist, the ignition switch is usually the cause;shorted intermitently;.

To test the switch, connect that wire back to the powerpack, then disconnect that same color wire from the ignition switch. If the engine runns okay, replace the switch.