'94 Force 120 Loss of Power...HELP!...*UPDATE 6/24*

[GBOverKill]

Hi Folks,
I've read alot of the previous posts on here and done just about everything, I'm stumped. I'm on vacation next week and planned on doing alot of tubing, etc. with the family. The engine has run perfectly the last dozen times I've had it out this year.

Here's what happened....the other day I was out running at WOT when all of the sudden the motor slowly lost power grrrrrr....grrrr....gr..and died. I was able to restart and get back to the docks but only what seemed to be about 1/2 power (rpms & speed).

Here's what I've done so far...
-Checked the fuel system and replaced inline filter, cleared the tank vent. Seems to be getting plenty of fuel.

-Replaced all the spark plugs (although they all looked fine).

-Checked for spark and have spark on all 4 cylinders.

-Checked compression and it's good on all 4 cylinders (130-140psi).

-All wires under the cowl appear normal and connected.

My mechanic (which unfortunately is 2 hours away) suggested spraying some carb cleaner in each carb; which I will try today.

Any other ideas????

 

[pnwboat]

Re: '94 Force 120 Loss of Power...HELP!...on vacation next week!

Re: '94 Force 120 Loss of Power...HELP!...on vacation next week!

Be very careful about spraying automotive type carb cleaner into the engine. The engine depends on a mixture of oil and fuel to lubricate the engine bearings. Carb cleaner has no lubricant and depending on how much and how fast the motor is running, you may cause problems. I would advise against it.

Since you appear to have spark, it may be a fuel system problem, but first a couple of questions.
Does your primer bulb get hard when you squeeze it? With the motor setting level (not tilted up), do you notice any gas leaking out of the carbs when you prime it? When you were having the problem, did you happen to notice if the primer bulb was kind of sucked in or collapsed? If the answer is yes to the first question, and no to the second two, I would be inclined to replace the fuel pump diaphragm. Relatively inexpensive and easy to do.

 

[Unbalanced]

Re: '94 Force 120 Loss of Power...HELP!...on vacation next week!

Re: '94 Force 120 Loss of Power...HELP!...on vacation next week!

Spun flywheel? Check your timing.

 

[jm_bullard]

Re: '94 Force 120 Loss of Power...HELP!...on vacation next week!

Re: '94 Force 120 Loss of Power...HELP!...on vacation next week!

My 98 Force did the same thing a couple of days ago. It ran at half-throttle. When I checked everything listed above, it all seemed OK. Then, when cranking to head back to the dock, the magneto came apart and jammed the flywheel. I'm pretty sure that was the problem.

 

[GBOverKill]

Re: '94 Force 120 Loss of Power...HELP!...on vacation next week!

Re: '94 Force 120 Loss of Power...HELP!...on vacation next week!

Went out again this morning and here's the results and some answers to your questions....

- Primer bulb remains firm.
- Used the Merc carb cleaner and no change.
- No leaking fuel from the carbs at all.

What next?? Timing?? Something binding in the Lower Unit?? Is there an 'easy' way to check the timing? I have the manual but seems a little foreign to me.

 

[Unbalanced]

Re: '94 Force 120 Loss of Power...HELP!...on vacation next week!

Re: '94 Force 120 Loss of Power...HELP!...on vacation next week!

There is one check you can do without a timing light.

Remove the top (#1) spark plug. Use a screw driver or something similar that will fit in the spark plug hole that you can use to feel the position of the piston. Move the flywheel by hand until you feel top dead center or highest positon of the piston. Now look at your flywheel and check to see if the timing pointer is lined up with the 0 deg mark on the flywheel.

This is a very basic check to see if your flywheel is lined up. A timing light is necessary to check and test true timing.

 

[GBOverKill]

Re: '94 Force 120 Loss of Power...HELP!...on vacation next week!

Re: '94 Force 120 Loss of Power...HELP!...on vacation next week!

Thanks folks, I tried everything and....well....I brought it into a shop on Friday. :redface: Hopefully they will have it ready for me on Wednesday; I'm going on a vacation with it that's been planned for about 6 months!

All I ask for now is your prayers that it's nothing major and back to me by Wednesday. May the force be with me

 

[pnwboat]

Re: '94 Force 120 Loss of Power...HELP!...on vacation next week!

Re: '94 Force 120 Loss of Power...HELP!...on vacation next week!

Hopefully it's something simple and inexpensive, like the fuel pump diaphragm. Ignition parts can be pretty pricey. Good luck! Hope you get a chance to enjoy the boat on your vacation.

 

[GBOverKill]

Re: '94 Force 120 Loss of Power...HELP!...on vacation next week!

Re: '94 Force 120 Loss of Power...HELP!...on vacation next week!

UPDATE.....

Got the boat back today from the shop and all they would tell me is that is has low compression on the #2 cylinder. Now....I personally checked all the compressions myself before I brought it in with no problems. They said it needs a total rebuild or replacement for about $3k. I still think it may be a carb problem. I took it out today for a little bit and still has the same symtoms however I did notice this....

Forgive me if I don't know the correct terminology here but that flat metal plate that the throttle is connected to near the lower carb (in the left part of the photo)....when I put it at WOT (and the protruding metal piece on the plate goes all the way down to the stop screw) it seems to choke, hesitate, and growl before the engine kicks in.....any ideas????

http://s650.photobucket.com/albums/uu226/kustomindustries/?action=view&current=IMG00210.jpg

 

[moparman]

Re: '94 Force 120 Loss of Power...HELP!...on vacation next week! *UPDATE*

Re: '94 Force 120 Loss of Power...HELP!...on vacation next week! *UPDATE*

go back and run another compression check on the motor and give us the individual readings[not 130 to 140] please.If the compression test you did was done correctly,its hard to believe a cylinder drops out while they have your boat. They[repair shop] might have misread the gauge ,or they may be yanking your chain.I would get another check myself,and see what you have and post it on another thread so we can see what you have.I hope the readings are good and then you can get to the [hopefully]real problem. MOPARMAN

 

[Unbalanced]

Re: '94 Force 120 Loss of Power...HELP!...on vacation next week! *UPDATE*

Re: '94 Force 120 Loss of Power...HELP!...on vacation next week! *UPDATE*

From your first post, you mentioned that you were running along at WOT and then suddenly the engine went south. The motor is not going to suddenly loose some compression on the #2 cylinder unless there was some major mechanical failure like a holed piston, broken ring or reed. This is where an accurate compression test is essential. As long as the compression numbers are within 10psi of each other and above 100psi, you're good. The shop you took it to should have given you the numbers and should have been wiling to demonstrate the test with you present before quoting a $3K rebuild. At this point I wouldn't trust that shop.

At WOT you could have sucked something through the fuel system and clogged a filter or jet. I would clean/replace all filters and remove and clean the carbs.

The other possiblity is that the flywheel has spun on the crankshaft and has therefore altered the timing. This is difficult to see without removing the flywheel. You'll have to verify the timing with a timing light.

 

[GBOverKill]

Re: '94 Force 120 Loss of Power...HELP!...on vacation next week! *UPDATE*

Re: '94 Force 120 Loss of Power...HELP!...on vacation next week! *UPDATE*

Ok, thanks for the posts....did another compression test myself....
#1=140
#2=135
#3=135
#4=140

I've already flushed the gas tank vent and changed the in-line fuel filter. Primer bulb is fine too.

I took it out yesterday, it was a bugger to keep running once started. I turned the idle up a bit because when I went to put it in gear, it immediately died. We ran it up to about 35mph and it would occassionally sputter at WOT. It still makes that groaning, choking at first when I put it down to WOT as described in my previous thread. One thing I did discover is that if I pumped the key (choke) when it was sputtering, it would recover and run fine??.

 

[chitownborn]

Re: '94 Force 120 Loss of Power...HELP!...on vacation next week! *UPDATE*

Re: '94 Force 120 Loss of Power...HELP!...on vacation next week! *UPDATE*

i agree with pnwboat, fuel pump diaphram, had the same issue with mine, changed it and it ran great. good luck don

 

[Unbalanced]

Re: '94 Force 120 Loss of Power...HELP!...on vacation next week! *UPDATE*

Re: '94 Force 120 Loss of Power...HELP!...on vacation next week! *UPDATE*

i agree with pnwboat, fuel pump diaphram, had the same issue with mine, changed it and it ran great. good luck don

+1 for fuel diaphram.

One thing to note when you change your fuel pump diaphram. Check the bolt holes.
The bolt holes were quite a bit to small in the recent diaphram I got. Open the holes up so the bolts don't cause issues when the pump is assembled.

 

[GBOverKill]

Re: '94 Force 120 Loss of Power...HELP!...on vacation next week! *UPDATE 6/24*

Re: '94 Force 120 Loss of Power...HELP!...on vacation next week! *UPDATE 6/24*

Ok, so I changed the fuel pump diaphram today. Ran down to the lake and it ran GREAT for about 5 minutes then back to the same old thing.....growling, hesitating when I go to give it some throttle.

Now what folks???

 

[moparman]

Re: '94 Force 120 Loss of Power...HELP!...*UPDATE 6/24*

By changing the pump diaphragm, its possible that you loosened a restriction in the fuel system[ whether by disturbing the fuel lines or more pressure with the new diaphragm],and the crap they sell for gas now days with alcohol in it tends to eat at the fuel lines from the inside out. I guess what i'm trying to say is look at the carbs to see if you have trash in them. Keep us posted as to what you find. Just my two cents worth. MOPARMAN

 

[jrtredo]

Re: '94 Force 120 Loss of Power...HELP!...*UPDATE 6/24*

Have you checked the timing yet? i was having similar issues and it turned my timing linkage cracked and my timing fell off