Gauges for 89 Force 85 hp

Picked up an older deck boat and the outboard is totally "out of sight." What I need to do is add a water pressure gauge, water temp gauge, and trim/tilt indicator. I would like to add a vacuum gauge (makes trimming for economy easier), but that may be too difficult. I found a complete set of manuals online for the 89 Force 85 hp, but they don't show enough to do the job. Any assistance would be greatly appreciated!!!

Thanx - Smitty

Thanks, Gunner1. I saw the threaded plug on top of the head. I'm not buying new gauges. I have quite a few left over from old installations. I'm trying to fix her up right and at the right price. Thanks again. - Smitty

Re: Gauges for 89 Force 85 hp

Actually, when you buy the gauges, they'll have the instructions to install them. There should be a tapped port on top of your cylinder head for the water temp/pressure gauge. You may have to put in a "T" to run both. As for the trim/tilt gauge, I have no idea how you would retrofit it to that motor.

Re: Gauges for 89 Force 85 hp

When you look at the manifold, on the right hand side (actually port on the engine) behind the choke solenoid is a square section. If you were to split the manifold, you would see that this is hollow and is actually one of two balance tubes between the carbs. This side balances all three so it is the one to use.

If you have an oil return tube between the top two carbs, you can put a tee in the rubber hose and you should get a steady reading because this hose is always under manifold vacuum and the fitting is not metered--So: even when it is returning oil, the vacuum should remain constant. You could also unscrew the fitting and screw in a tee fitting.

However, it would probably be best to take the little extra effort and drill and tap another hole here for a brass fitting. The casting is around 1/8 inch thick, so you may want to lightly screw in the fitting and epoxy it in place. If you are lucky and have the return hose you may be even luckier and have an extra boss below it that can be drilled and tapped. Then you are gold.

You do not want to use the nipple on the bottom of the manifold below the third carb. This fitting returns dripped and spit-back oil and fuel from the carbs, in the airbox, and has a metered hole in it so that when no oil is present in the air box, it will not suck too much air and lean out the bottom cylinder. So: manifold vacuum may not be accurate and may also vary with running conditions.

Behind the top of the head you will also see a rather large boss. This can also be drilled and tapped for either water pressure or water temp.

Re: Gauges for 89 Force 85 hp

Thanx Frank - I found the areas you were refering to. I think I will "T" into the line between the top carbs and run a line to the console.

There are a few other things that need to be done on this setup. I still need to install a "local" trim switch on the motor and have almost completed the hydraulic steering. Sooner or later, it will be ready for fishing.

Thanks again guys,
Smitty