1988 Force 125 very doggish

[Kevincem]

I have several problems with a 1988 Force 125 that I have just purchased. I am only able to run at 4500 rpms. The motor is on a 19’ Bayliner Capri open bow. The 1988 Force 125 is a 1251X8A. I have ony been able to get it up to about 25 MPH by the boat speedo. I do not have much information about the prop that is on the boat. I do have the original prop but have not used it yet. It was in the shop getting the nicks taken out. I guy I bought the boat from said that the prop that I have on is the better of the two. What can I do to get more out of this engine? I am able to pull a skier as long as they have strong arms and don’t mind being under water for a minute or two. What is the best prop for this engine? Where can I get one. I have heard good things about the Hustler props. Any strong opinions out there?<br /><br />The other problem I am having is that the engine will not idle. I just had a tune up done on it and I did see an improvement. However when I am coming into the dock or trailering the boat I have problems because the engine will stall after about 30-60 seconds. I am not sure what the RPMs are at idle. I will be checking that info during my next outing. The other problem that I have noticed is that the tube that connects the engine and the peehole has a crack in it. Is it used for just water or is it part of the exaust bellows? How big of a problem is this? I just had the water pump replaced.

 

[roscoe]

Re: 1988 Force 125 very doggish

Quite a few items to cover here, to try to narrow down the posibillities.<br /><br />Your engine could very well be running on only 3 good cylinders, and one weak one. Could be caused by low compression or a lean carburator.<br /><br />What did your tune up consist of?<br />Were the carbs rebuilt?<br />Was the compression checked?<br />Have you checked for a strong spark on all 4 cylinders?<br /><br /><br />You have to check compression, spark, and fuel delivery to each cylinder.<br /><br />Peehole tubing can be replaced, but should not effect the operation of the motor.<br /><br />Idle speed can be up around 900 on this motor, but would not go higher. Better to find out why it is running so poorly.<br /><br />Also a good idea to get rid of all the old fuel, and clean out the tank if possible.<br /><br />Make decisions about prop selection after the engine is running properly.

 

[ChalkBoy]

Re: 1988 Force 125 very doggish

I had a Force for years...I had the same problem.... It most likey is the powerpack. There is two of them. Each one is responsible for two of the cylinders. Most likey one of them is weak or not functioning at all. You can order them over the internet. Mercury will want about 400 bucks or so. It can be tricky to install also. My engine ran like a champ after I replaced one of the power packs. All of my problems went away! When Mercury took over the Force, around 1990, (manufactured by US Marine at the time)one of the first things they did was to replace the ignition system. Good Luck!

 

[brinboat]

Re: 1988 Force 125 very doggish

Originally posted by Katchem&Eatem:<br /> I have several problems with a 1988 Force 125 that I have just purchased. I am only able to run at 4500 rpms. The motor is on a 19’ Bayliner Capri open bow. The 1988 Force 125 is a 1251X8A. I have ony been able to get it up to about 25 MPH by the boat speedo. I do not have much information about the prop that is on the boat. I do have the original prop but have not used it yet. It was in the shop getting the nicks taken out. I guy I bought the boat from said that the prop that I have on is the better of the two. What can I do to get more out of this engine? I am able to pull a skier as long as they have strong arms and don’t mind being under water for a minute or two. What is the best prop for this engine? Where can I get one. I have heard good things about the Hustler props. Any strong opinions out there?<br /><br />The other problem I am having is that the engine will not idle. I just had a tune up done on it and I did see an improvement. However when I am coming into the dock or trailering the boat I have problems because the engine will stall after about 30-60 seconds. I am not sure what the RPMs are at idle. I will be checking that info during my next outing. The other problem that I have noticed is that the tube that connects the engine and the peehole has a crack in it. Is it used for just water or is it part of the exaust bellows? How big of a problem is this? I just had the water pump replaced.

 

[brinboat]

Re: 1988 Force 125 very doggish

This sounds like a classic Force problem: Low compression caused by a carbon buildup.<br />For whatever reason the cross scavenged Force engines have problems with modern fuels. They constantly build up carbon deposits which reduce compression by both the build-up on the cylinder walls and the restriction of ring movement.<br />If you are lucky a treatment with a product like Mercury engine tuner or Macmillan ring-free will restore some of your lost compression.<br />The unfortunate alternative is an engine rebuild.<br />So check the compression (It should be about the same for each cylinder, 115-130 lbs.) If it isn't, go with the engine tuner and then recheck the compression. Hopefully that will do it.