*89 Force 125 - Won't run WOT

[Triphammer]

My 89 125 Force won't let me run WOT. I can run @ 4800 all day but when I try to run WOT (5200) it falters. Seems to shut of for a 1/2 second & start right back up on it's own. It'll keep doing that till i pull the throttle down to 3500 then I can push back up to 4800 & stay all day.

Fuel use sems high, too. 3000 lbs boat motor people & gear gatting about 1 maile a gallon on smooth water.

This may be normal. I haven't gotten to 5200 or even 4800 until this past week when I propped down to an 11P x 14 from a 14 x 14.

 

[jerryjerry05]

Re: *89 Force 125 - Won't run WOT

You sure of the pitches??
An 11x14 should be screamin.
A standard prop should be 13 1/2 X 17 maybe a 19
Post pics of the props?
Excessive fuel use could be the pump diaphram has a tear?Take it apart and see?
Do a compression/spark test.
Any water in the fuel?
Over heat system ok? test it.

 

[Triphammer]

Re: *89 Force 125 - Won't run WOT

I may have the numbers out of order - I'm saying 11 inch pitch/ 14 inch diameter. With a 14 inch pitch I can't get above 4K with a standard load - about 2500 lbs.
I get about 40% slip with a 14 in pitch, 25 - 30 % with the 11.

I'm going to pull my pump this week. My son & I were wondering if the falter may be a lack of fuel.

This may have been a problem from day one. I'll post here what I find.

 

[jerryjerry05]

Re: *89 Force 125 - Won't run WOT

Do a compession test FIRST!!

 

[Jiggz]

Re: *89 Force 125 - Won't run WOT

Correct me if I'm wrong but I believe the maximum height clearance of the prop from the anti-cavitation plate is only 13.75". So you could be referring to a 11" diameter and a 14" pitch instead. As mentioned the standard is 13.5" diameter with a 17" pitch or 19" pitch. the faltering at WOT could be timing related or it could also be fuel related. With a see-through fuel filter you can readily tell if it is fuel related as the fuel filter will be empty if the fuel pump cannot keep up at WOT. Otherwise, if the fuel filter stays full, then it is most likely a timing issue.

 

[Triphammer]

Re: *89 Force 125 - Won't run WOT

7 5/8" center of prop shaft to Cav plate. My 14" diameter prop has a 7" radius. Compression test tomorrow. I've already ordered the fuel pump diaphram & ( just for good measure) TWO carb kits.

I thought it may have been timing so I worked with that quite a bit while on the water. I followed the manual & the stickied tutorial video quite closely when I set the timing, originally, so I only went a little up & down & back to where I started.

 

[Triphammer]

Re: *89 Force 125 - Won't run WOT

Do a compession test FIRST!!

120 - 130PSI all four cylinders

 

[jerryjerry05]

Re: *89 Force 125 - Won't run WOT

The standard props can run from 13" to 14" and the pitch from14x13
to a 13x19 ,13x17 13x15c (c-cupped).
The lower pitches are for bigger boats and pontoons.
Pic of your prop?
Top post has a thread from FrankA called a linc and sinc. Do this and see if the carbs are set up right

 

[t money]

Re: *89 Force 125 - Won't run WOT

Does the motor sound like this:

http://forums.iboats.com/force-chrysler-outboards/1987-force-125-hp-493622.html

For me I tried:
new fuel hose (could have a pin hole letting air in)
new diaphram (same as above)
Try using a new gas can (could have debris blocking the hose)
Check your carbs could block flow at WOT

I've tried all of that above and now we have moved on to rotor/stator and power pack issues. (this is what you hope it isn't cause these parts are spendy)

hope that helps

 

[Triphammer]

Re: *89 Force 125 - Won't run WOT

Does the motor sound like this:

Exactly!
I've rechecked timing & have a fuel pump kit & two carb rebuild kits coming. I'll replace hoses at the same time as a couple are cracked. Don't see any leaking but WTH, they're cheap.
It does sound like a spark issue but I hope not. Tha'st a lot of expensive quessing, right there.

 

[foodfisher]

Re: *89 Force 125 - Won't run WOT

I didn't hear a spark issue. When the fuel was there, it ran fine. Fuel, probable air leak.

 

[jerryjerry05]

Re: *89 Force 125 - Won't run WOT

Sounded like water? Check the gas for water?.
Plugs all burning right?
I had a trigger lead on one motor go bad.
The connection under the shrinkwrap broke and it wouldn't operate when the throttle advanced?
I always change ALL the connectors when I work on a new project.
Change the fuel pump diaphram.