85HP Force Lower Unit oil

[TexasBayFisher]

Re: 85HP Force Lower Unit oil

The block is usually too massive to warp. The head, however, can warp. Put it on a flat pane of glass to check. Manual says you can take off .010 to true it but I have gone .060. Careful, .060 increases the compression ratio and may cause detonation. If she pings, reduce timing a couple of degrees and go to higher octane fuel.

More than likely though, the head gasket was ruined. If it is still holding compression, Permatex on the fiber portions may stop the water leaks.

Frank, I've since replaced the cylinder head with a used Chrysler head along w/new gasket and good thermostat. All is well now and I've run the boat several times without issues.
When this happened I was running Amsoil synthetic for pre-mix and before running the boat that day I mis-judged the amount of gasoline the tank would take, but only after I had already put the oil in. So the mixture I was running at the time was somewhere around 32:1! I believe this saved the bearings and the pistons/rings. A silly mistake that likely saved the engine.

 

[kooken]

Re: 85HP Force Lower Unit oil

hi, first time on hear, hi to all. i have a 1987 force 125 HP. was going to change the lower unit oil, removed a screw that i fownd out later was the linkage screw. but it draned out from this hole. the oil was vary black, but no water in it, when i got done and tryed it it went in and out of gear ok so i did'nt mess anything up, thank god. then i fownd the right screw to drane, hears the thing, the tool you put in the hole to turn it out is brock off in it. can't get it out. so is it ok to drane from the linkage screw hole from now on. someone on hear sed never take the linkage screw out, could mess up shifter. thanks bob

 

[kooken]

Re: 85HP Force Lower Unit oil

hi, first time on hear, hi to all. i have a 1987 force 125 HP. was going to change the lower unit oil, removed a screw that i fownd out later was the linkage screw. but it draned out from this hole. the oil was vary black, but no water in it, when i got done and tryed it it went in and out of gear ok so i did'nt mess anything up, thank god. then i fownd the right screw to drane, hears the thing, the tool you put in the hole to turn it out is brock off in it. can't get it out. so is it ok to drane from the linkage screw hole from now on. someone on hear sed never take the linkage screw out, could mess up shifter. thanks bob