1988 Force 125 WOT 4200 RPM

[j1984k5]

I have a 1988 force 125 model 1254X8A on a 1988 Bayiner 1800 Cobra.
My problem is I can't get it to make over 4200 rpm (35mph on the speedo) I know that elevation will hamper the motoer output we are a 6000 ft here. The boat was stored for 4 years before i bought it and supposedly it was winterized. It took me 2 days to get it started fuel mixture needed to be set and the timing adujsted. I tore apart the carbs twice and the fuel pump, both had sand and debris in the bowls and filter respectively. I relpaced the primer bulb and hose and hose from pump to carb. replaced diaphram in pump. I haven't rebuilt the carbs (just cleaned them) I don't know what rebuild kit to get because my needle and seat are pressed in not screwed in.
The operating range is 4500 to 5500 rpm as per the data plate on the motor. I replaced the prop for a 13 1/4 x 15 and that didn't make a diff. The compression was checked last year @ 120 psi @all 4 cylinders.
I don' Know if this is enough info but any help woul be appreciate. I do have the seloc manual for it and the parts catalog.

 

[j1984k5]

Re: 1988 Force 125 WOT 4200 RPM

the prop that I took off was a ss 13 1/2 x 17, the local boat shop here in colorado springs CO. said that it was way to much prop for the altitude around here. But I still had the same 4200 rpm but 37 mph on speedo and it took a long time to plane.

 

[1730V]

Re: 1988 Force 125 WOT 4200 RPM

6000 feet will make any outboard wheeze. They're right it's overpropped.

You may also want to aske them what carb. jets they recommend.

 

[Frank Acampora]

Re: 1988 Force 125 WOT 4200 RPM

If you want to spring for bigger bucks, see if you can find a good lower unit off a 90 or 85 HP. Anything from 79 to 89 one piece lower unit will fit. It should have 2 to 1 gears instead of the 1.78 to 1 gears now in your lower unit. Even with the 17 pitch prop, you should pick up about 400 RPM and 2-4 MPH. ----Depending on your hull.--- Even though changing the gear ratio is like lowering the prop pitch---IT WORKS BETTER! I don't know why, it just does. I did it on my 1988 125 and my '79 140. Of course, fuel use will go up by 10-15%. Also, a Stainless prop will give 200 rpm more than the same prop in aluminum.

 

[1730V]

Re: 1988 Force 125 WOT 4200 RPM

"Also, a Stainless prop will give 200 rpm more than the same prop in aluminum."

Not sure about that. Aluminum flexes more thus causing more slip which equates to more RPM.

 

[j1984k5]

Re: 1988 Force 125 WOT 4200 RPM

thanks. I was reading some other posts and it seems like I could stand to decarb the engine. Seafoam seems to be the product of choice in these forums. Where do I get it and about how much does it cost.

 

[rudedude]

Re: 1988 Force 125 WOT 4200 RPM

I get it at auto parts stores. If you get it at a boat shop they charge more for it.

 

[Frank Acampora]

Re: 1988 Force 125 WOT 4200 RPM

Addendum to my last post: If you get a lower unit off an 85 hp be sure it has 2 to 1 gears. I think during some years, some 85s had the higher 1.78 to 1 gears.

In addition to flexing more, aluminum props generally have thicker blade sections for adequate strength. This translates into more drag. It takes more horsepower just to screw the prop through the water. Thus less horsepower is available to propel the boat. Stock props are brutally thick; aftermarket props are better but still slower than the equivalent prop in stainless.

 

[j1984k5]

Re: 1988 Force 125 WOT 4200 RPM

Well I just finished the decarb, lots of brown junk on the splatter board ( running on muffs) I don't really notice any difference in the way it runs, I assume it should at least sound different. (I won't be able to take her to the lake until saturday). Also I was checking the spark by removing the plug wires to see if there is a noticiable drop in rpms, #1 & #2 not noticiable until you put it backon then it really changes. #3 & #4 engine dies when wire is removed but fires right back up. Is this normal? other than the lack of rpm's at WOT (4200) the motor runs great . idle is smooth and she sounds great. Any help would be great

 

[j1984k5]

Re: 1988 Force 125 WOT 4200 RPM

Oh I forgot to add this to the last post. What carb and fuel pump kits do I need? My carbs don't have the screw in needle and seat. Also will this help with the primer bulb going soft. It gets kind of soft(needs about half a squeeze to get firm) when it is running but never sounds like its starving for fuel even @WOT. Engine model 1254x8a

 

[Frank Acampora]

Re: 1988 Force 125 WOT 4200 RPM

Ahhhhhhh! For the future, don't check spark by pulling off a wire. An open spark circuit can overload and damage the CD box. And you might get nailed with 50,000 volts--a real thrill. If you want to check while the engine is running, use an inductive pick-up timing light. It will flash when voltage goes to the plug. Won't tell you if the plug is bad or fouled though.

 

[j1984k5]

Re: 1988 Force 125 WOT 4200 RPM

Thanks Frank it did shock me a little at every wire. Should I feel the spark through gloves and the plug boot? Also If you could answer the question about the rmp drop and it dying from my previous post. And the question about the fuel pump and primer bulb

 

[j1984k5]

Re: 1988 Force 125 WOT 4200 RPM

Well today I finally got the boat down to lake for a run after the decarb. Seemed to run a bit better after I got it started I think The fuel and oil mix is a little rich. But usually after warmed up I would not have any problem getting it started after shutting it of and letting it sit for a while(quarter turn and it would fire). Today though it was always a struggle to get it started, plus it stalled when put in gear from idle alot. This never happened before. I'm not sure if I need to decarb again or not? On the bright side I picked up 300 rpm ( up to 4500) and 2 mph (up to 37) @ WOT but my take off (holeshot) and time to plane seemed to suffer. I'm not sure why. I need a question answered can I use a regular automotive inductive timing light to check my timing, or do I need a special one? I checked with my light and I the timing marks don't line up except for the 0 mark the other three don't even come close. I had this set by my local boat shop so I figured it was right but it doesn't seem right ( tried it and messed it up). I'm no stranger to timing v8 chevy's and doing regular maint. on my own vehicles, but the seloc manual doesn't make it real clear. I'm pretty sure this would affect my WOT rpm.

Any help would be great.

 

[Frank Acampora]

Re: 1988 Force 125 WOT 4200 RPM

The 0 degree mark should line up or be about plus or minus 2 degrees only at idle. The other three marks: the center mark or long line is 30 degrees advanced and should line up with the reference at full throttle. It is more important to have this setting correct than the 0 degrees at idle, since the proper idle speed depends on carb opening, timing position, and prop pitch. A higher pitched prop will load the engine more in gear and require a slightly more opened carb and advanced timing to acheive the proper 700-750 RPM. If you have an adjustable reference line then check that 0 degrees lines up with it AT TDC. (A loose flywheel key that does not fit snugly in the keyway or bent reference tab can also cause incorrect indexing of 0 degrees.) To do this, with all plugs out turn the flywheel by hand while you probe the top piston with a screwdriver to feel when it comes up to TDC. You will need to rock it back and forth and develop a "feel" for it since there is very little piston movement at TDC. Factory uses a special tool to measure it at 32 or 36 for older engines--more accurate and faster that way

Addendum: It is possible to time the engine to 0 degrees at idle and have the 30 degrees way off even if the reference is correct. Look at the top of the linkage tower. the two plastic pieces that connect the tower to the trigger lever should be about 3/8 to 1/2 inch apart. If they are way farther apart or much closer together, the WOT timing will be advanced or retarded respectively. So before you go crazy, check this setting. If incorrect, set back somewhere between 3/8 and 1/2 inch THEN reset carbs and timing according to the manual. See! everything is inter-related. Changing one small thing can affect others.

Another thought: The manual is not clear on this: If you have the black plastic fittings with the adjusting screw that goes all the way through one with a locknut on the outside, THEN: the fitting with the locknut is attached to the outer hole (if there are two) of the trigger arm. The adjusting screw goes to the inside (closer to the crankshaft). DO NOT ATTEMPT TO ADJUST TIMING WITH THE ENGINE RUNNING! To do so invites removing fingers or large parts of them quickly and violently. This gets blood all over the engine and destroys the aesthetics of the factory paint job.
You can use a regular automotive timing light with the inductive pick-up on the top cylinder plug wire (#1). You can set timing at cranking speed with the plugs connected to a plug tester or grounded so the engine will not start. If you do it this way, The timing needs to be set to 32 degrees since rotation of the flywheel at running speed (wide open throttle) will move the triggers and retard timing. I prefer to check timing on the water with the engine running then stop it and adjust if necessary-Takes a little longer but I feel that it is more accurate--just my opinion.

If you suspect the timing is off, then get a Clymers manual or search for threads here on synchronizing throttle and timing. Re-set everything to factory specs. and see what happens then.

 

[j1984k5]

Re: 1988 Force 125 WOT 4200 RPM

Thanks Frank I'll Check.