1985 Force 125 Tuning tips/help needed.

[Racer]

Hello.

I just bought a used 1985 19' Bayliner with a 125 Force engine and looking for some tuning tips.

The engine seems to run fine, but it sure seems like it does not have much power starting off from idle. Once it finally gets going, it pushes the boat along at around 35mph which isnt too bad for that heavy of a boat. Maybe that is all it has I dont know.

Anyway, the guy I bought it from just rebuild the carbs. (Yeah, I thought oh boy). I think its running too rich. He did not have the chokes setup quite right and there was a binding in the linkage so the choke would not shut and I think he richened it up so it will start. I fixed the linkage and it starts easily now.

Anyone have a base line where the mixture screw should be set from completely closed? I figure that would get me close anyway.

Also I would like to check the timing. On my flywheel I see 2 lines. Any pictures I have seen shows actual degrees engraved in the flywheel. I am guessing 1 line is TDC and the other one is the timing mark?

Thanks for any help you can provide.

Jeff

 

[4runneradam]

Re: 1985 Force 125 Tuning tips/help needed.

Mine has the same 2 timing marks. First one on the left is the timing at idle, second one is timing at WOT.

 

[Racer]

Re: 1985 Force 125 Tuning tips/help needed.

Ok cool. I will have to check the timing to make sure its right. I am guessing you want to set it a little on the slow side if you are setting it at cranking speed?

 

[baxtr]

Re: 1985 Force 125 Tuning tips/help needed.

Ok cool. I will have to check the timing to make sure its right. I am guessing you want to set it a little on the slow side if you are setting it at cranking speed?

ground all your plugs, disconnect the neutral switch (microswitch under the throttle tower) go to WOT, have someone turn the key so the starter spins the motor and check the timing, set to 2 degrees less and it should be right on when it is actually running.

 

[baxtr]

Re: 1985 Force 125 Tuning tips/help needed.

Straight out of a force manual:


Starting mixture screw is 1 full turn out from lightly seated.

1 With boat tied securely to dock, start motor and run until fully warmed up.

2 Set controls to high-idle neutral position.

3 Turn idle mixture screws slowly open, conuterclockwise, until motor loses power and begins to roll due to an over-rich mixture. Note this position

4 Slowly turn screws closed, clockwise, until motor runs smoothly and begins to pick up speed. Continue turning clockwise until motor pops or stalls due to lean mixture. Note this position

5 Set screws halfway between the two positions


I then go 1/8 turn richer just to be safe, rather be rich than lean

 

[Racer]

Re: 1985 Force 125 Tuning tips/help needed.

Here is an update on my engine. Thanks to all that have helped.

I went out and got a compression tester. I took out the plugs and found that #3 plug was completely clean. First thought was oh boy. Dead cylinder. Checked compression. It was a little over 150 on all 4 cylinders which is in spec from what I read.

I then checked for spark. 1,2,4 all spark, #3 nothing. I figured it was the coil. I then got to looking around and noticed one of the wires from the primary did not seem to be connected completely. I snapped the connector back together and sure enough, spark on #3. WOO HOO!

I then proceded to check the timing and it seemed pretty close, so I did not mess with it. I adjusted the mixture screw on the carbs and it seem that just over 1 turn out was the sweet spot.

I put it out on the lake today and immediately when I hit the throttle it jumped up on plane. It was great! I gained like 10 mph at top speed.

The strange thing is that at no time did it ever seem like the engine had a miss. It never ran rough or anything. Wierd!

Anyway, thanks to all that have provided help. I was a little disappointed in the performance before and now I am very happy how things run!

Jeff