93 Force 90HP dies when in water

[mrobertson]

Hello guys,

I've got a 1993 Force 90HP. Right now on the garden hose the motor will start up great. It will idle all day long and if i put it in gear i can throttle it up and down with no problems.

However, when i put the boat in the water i get different results. At the ramp it will start up great, sit there and idle fine. As soon as i put it in gear, forward or reverse, it will start to choke up and just die. I can restart it a couple of times and do the same thing but after a few retries it becomes hard to start.

I have verified compression :

#1 120
#2 118
#3 120

I also set the timing at WOT like the manual suggests, (i think 32 degs).

At this point i suspect it is a fuel problem. I think it MIGHT be flooding out and thats why it's so hard to start after a few tries. By the time i drive home from the ramp i can hook it up to the hose and it will start right up, AGGRAVATING!!!

I have also tried pumping the primer bulb when in gear with no difference.

What do you suggest? I am contemplating buying carb/seal kits for all 3 carbs and rebuilding and cleaning them.

Can anyone suggest anything else?

Thanks,

Mike

 

[eurolarva]

Re: 93 Force 90HP dies when in water

I would test spark first. Sounds more like a cylinder not firing. Pull your plugs and see if one is cleaner then the other. That would be the bad cylinder. Could be carb but typically a bad carb wont idle but tends to run at medium and full throttle pretty well.

 

[mrobertson]

Re: 93 Force 90HP dies when in water

Plugs are all good. I have verified spark outside the cylinder. However i know it's possible to have no spark while threaded in the cylinder.

How do i test for spark while the spark plug is actually in the cylinder?

 

[steamplant]

Re: 93 Force 90HP dies when in water

I had the same problem. It turned out that my idle RPM was low. To test it, grab the throttle linkage at the engine and manually increase the RPM slightly while you have your buddy shift the control to gear. If it stays running you can make a permanet idle adjustment with the small bolt on the tower. I think my 85 HP runs at around 900-1000 RPM at idle. Never had another problem, good luck

 

[Docdoc]

Re: 93 Force 90HP dies when in water

Could be that the idle is too low. Remember that proper idle must be set with the boat in the water and in gear, I've done this at the boat ramp with the boat still on the trailer. It could also be that the idle mixture needs to be set. If you don't have a service manual, get one and use the procedures it outlines for setting the idle mixture.

 

[baxtr]

Re: 93 Force 90HP dies when in water

Ditto to Docdoc

leave it on the trailer and adjust to proper idle speed