1988 125 Force

[SkiDad]

Re: 1988 125 Force

I'm no expert - Frank is the man for this. But it looks to me like your plate height is about 1" above bottom of your boat. So that looks good. Have you checked your carb that it is opening all the way ? Have you checked your timing - there is a video at the top of this forum to check all of that that Frank made last year. I need to check my timing too - i suspect it is right but never have checked it.

 

[foodfisher]

Re: 1988 125 Force

On the side: Check your transom for soundness. All that rust colored bleeding at your thru hull plastics caught my attention.

 

[jerryjerry05]

Re: 1988 125 Force

I'm a little late adding this but just got home.
Remember it's a 125 any more power you need to get a bigger motor.
That said,the low compression could be the guage,since all 4 are the same.
The 4600rpm's is about 900 too low.
Is the tach right?
The motor is set about right on the transom.
The cavitation plate should be even with the bottom of the deepest part of the bottom.
1 in up or 1 in below shoudn't make too much difference.
Like Food said,the thru hulls look damaged and possibly leaking.
The hull could be saturated with water.
The weight and load can have a lot to do with speed.
Full tank of fuel, coolers,skis,and a bunch of people can hurt performance.
Then is the trim/tilt functioning correct?
My boat a 21 with twin 85's no matter what I do and no matter what the load I can't get any more that 32.
Full of fuel and 4 people same as just running with me alone.
My last 21 had about 1000 pounds of saturated foam in the hull.???

 

[SkiDad]

Re: 1988 125 Force

edit: not applicable to this thread. Should have started my own

 

[bowhunter304]

Re: 1988 125 Force

You guys had me worried about my hull so I checked it out.there's an open spot in the bottom of my boat for water to go out. a lot of rusty hooks down there from the kids. found one where the motor bolts on. I think that's where the rust is coming from. everything is fiberglass in no wood or foam showing.if it is saturated how do you check it and how do you fix the problem

 

[jerryjerry05]

Re: 1988 125 Force

The only way to fix saturated foam is block the front of the boat way up in front.
Then try to blow air through the hull drying it out.That way would take a LONG time.
Or depending on the make you'd have to seperate the hulls and remove the foam.BIG JOB!!
The first thing is contact the manufacturer,get the specs on the boat.
Weight and any other info and then take it and get it scaled and see if it's too heavy.
The boat I had with the saturated foam, the manufacturer(Bayliner) neglected to install drains between the compartments.
That way when it would get water in it wouldn't drain and just settled in and soaked the foam.
Like I say contact the manufacturer and get the specs.
If your boat is uncovered a lot.It could have a lot of water?

 

[foodfisher]

Re: 1988 125 Force

Start with the drain plug.( easiest) Remove the fitting (flanges) and poke around the inside (between the skins) with a screwdriver. Soft and giving = bad news. Another way is to drill some holes into the transom from the inside (stop short of the outer skin) and check the wood bits coming out. Dry and wood colored = OK. Wet and dark = not. If it's bad, that's covered very well in the restoration forum.

 

[bowhunter304]

Re: 1988 125 Force

I checked the transom and foam no sign of water damage. Did another compression test with a different gauge and got 140 on the top two cylinder and 135 on the bottom two .put a timing light on it and it was advanced too about 35 to 37 so I put to 28 like the video could that be the problem

 

[jerryjerry05]

Re: 1988 125 Force

You changed the timing.
Probably not a good idea.
Usually the timing doesn't change unless the trigger/stator has been changed.
Or the linkage has broken.
Go through the help stickies and do a static timing and put it at 28

 

[bowhunter304]

Re: 1988 125 Force

4 years ago when I got the boat it only went 30 mph 3500rpm with a 17 pitch prop.About every other weekend it started to lose power. Started checking the motor and found the hot foot throttle wouldn't open all the way. Then found the black linkage on the timing was cracked and sliding so I had one made out of aluminum then found the carb linkage moved to after fixing everything I put new factory reeds in and then seen the cages were wavy I honed them level by hand.Then rebuilt the fuel pump .got 40 mph with 4600 rpm with one person .two days ago I did the link and sync like the video said. The timing was advanced too about 35 so I put it at 28 then did a carb out on it .today checked the compression and it 153psi on the top two bottom two is 150psi with the same new gauge any other suggestions

 

[jerryjerry05]

Re: 1988 125 Force

If the static timing is set at 28 and your linkage is opening the throttle all the way.
Try pushing the throttle lever all the way, then go back and see if the linkage on the carbs can go any farther.
I'd get another tach and make sure the rpm's are actually 4600.
They sell an item, called a Tiny Tach it hooks right to the top plug wie and connects to the block.
Comp is good.

 

[bowhunter304]

Re: 1988 125 Force

I just want to Thank everyone for the help.just wondering if a 4 cylinder automotive tach would work and
is the tiny tach a digital readout because I was thinking about replacing the factory one's which one is better
Soon as the weather brakes I'll get to the lake and try it out

 

[Jiggz]

Re: 1988 125 Force

I think you ought to check the motor first for a run after re-setting the timing. That fact it was initially timed too far ahead at 35 could actually be the cause of low power output thus rpm. The newly set static timing of 28 should be fine and you should run it first to check if it has improved performance. As for the tach, I would leave it alone for now but as suggested you can use a Tiny Tach (small with digital readout) as a back up or as a confirmation for the main tach. I put one on mine (tiny tach) and it is mounted inside the cowling and seems to validate my tach. And the answer to your question about using an automotive tach is NO.

 

[jerryjerry05]

Re: 1988 125 Force

You need an outboard specific tach.
Yours is a 20 pole tach.
Any Force tach from the early 80's to the early 90's
Should fit.The 50/85/125/150 all use a 20 pole tachs.

 

[fishnski14]

Re: 1988 125 Force

For more speed, You can put the engine on a smaller boat LOL

Seriously though. the first thing you need to do is check compression to be certain the engine is healthy. Good compression would be around 145 PSI. Poor compression would be one cylinder or more below 60 PSI or a difference of more than 10 PSI between cylinders. A cylinder at 20 or less would indicate a rebuild is necessary.

Next, check the carburetors to see if they are opening correctly. Watch the tutorial video at the to top the forum.

Check the current prop to see if the engine is overpropped or underpropped. The correct pitch prop will allow the engine to reach 5000-5500 RPM at full throttle. If you do not have a tachometer, you can either search for a 20 pole tach and permanently mount it in the dash or you can buy an inexpensive tiny tach with which many here on the forum have had good results. I have never used one.

Now if all that checks out well and you are still getting low speeds you can do some internal modifications and change to aftermarket reeds ( which I believe really don't do much). You can port the bypass side, but porting the exhaust side will actually yield less horsepower. Porting is the procedure where you manually grind the ports square, increasing the area and allowing the engine to make more horsepower.

View attachment 222517View attachment 222518View attachment 222519

Here is a 14 foot boat that delivers 60 MPH with a stock 125 and a 2 to 1 lower unit. Yeah, for reasons best left unsaid, the decal says 85.

However, understand that there is no magic bullet. I experimented for many weeks and months before I hit that speed. Understand that this boat is small and light, allowing the engine to push it fast. On a bigger boat It simply will not go that fast. It is basic physics.

On the forum, we can tell you some hints, but ultimately you must be motivated and do the work to get the most out of your engine.

Frank, what type of prop did you have on at the time. I have a 125 on a 16 ft boat and finding it difficult to keep the rpm's down.

 

[fishnski14]

Re: 1988 125 Force

For more speed, You can put the engine on a smaller boat LOL

Seriously though. the first thing you need to do is check compression to be certain the engine is healthy. Good compression would be around 145 PSI. Poor compression would be one cylinder or more below 60 PSI or a difference of more than 10 PSI between cylinders. A cylinder at 20 or less would indicate a rebuild is necessary.

Next, check the carburetors to see if they are opening correctly. Watch the tutorial video at the to top the forum.

Check the current prop to see if the engine is overpropped or underpropped. The correct pitch prop will allow the engine to reach 5000-5500 RPM at full throttle. If you do not have a tachometer, you can either search for a 20 pole tach and permanently mount it in the dash or you can buy an inexpensive tiny tach with which many here on the forum have had good results. I have never used one.

Now if all that checks out well and you are still getting low speeds you can do some internal modifications and change to aftermarket reeds ( which I believe really don't do much). You can port the bypass side, but porting the exhaust side will actually yield less horsepower. Porting is the procedure where you manually grind the ports square, increasing the area and allowing the engine to make more horsepower.

View attachment 222517View attachment 222518View attachment 222519

Here is a 14 foot boat that delivers 60 MPH with a stock 125 and a 2 to 1 lower unit. Yeah, for reasons best left unsaid, the decal says 85.

However, understand that there is no magic bullet. I experimented for many weeks and months before I hit that speed. Understand that this boat is small and light, allowing the engine to push it fast. On a bigger boat It simply will not go that fast. It is basic physics.

On the forum, we can tell you some hints, but ultimately you must be motivated and do the work to get the most out of your engine.

Frank, what type of prop did you have on at the time. I have a 125 on a 16 ft bass boat and finding it difficult to keep the rpm's below 5500