Used Boat ^ force 90hp

RGB5645 · Jul 20, 2009

I'm looking at a older Tri Hull bow rider with a 90 hp force.motor.

This will just be for fishing and nothing else. It also has a small gas trolling motor and electric one that needs a new bearing,

We plan to take it to the lake Wed or Thursday to see how it runs.

Have so heard many bad things about the force motor but the man that has it says it only has 20 to 30 hours on it. When was the last year these motors were built?

Any thing I should look and listen for.
How can I find out when the motor was manufactured.

any advice is appreciated.

RB

Dave K. · Jul 21, 2009

Re: Used Boat ^ force 90hp

get us the model number, usually stamped or tag inside the cowling, perhaps the bottom front part of the engine. possibly between '90 - '99 & probably made by mercury, but it's only a guess w/out that number.

mines an '84, 85hp. runs great, easy & cheap to maintain, very dependable. most important part that it was well taken care of before i got it & i take care of it.

john from md · Jul 21, 2009

Re: Used Boat ^ force 90hp

Parts are more readily available for the models made by Mercury in the late '90s. They are pretty basic engines but it all depends on how they were maintained as to how well they stand the test of time.

John

RGB5645 · Jul 22, 2009

Re: Used Boat ^ force 90hp

Dirk & John

Thanks for the information, we are going to the lake in the AM before it gets into the high 90's.

Will let you know how it goes. i hope all is okay as I miss my fishing trips.

sold our big old 18 foot I/O tri hull last year as it was getting to much to maintain and to cumbersome to load on the trailer by myself.

RGB5645 · Jul 22, 2009

Re: Used Boat ^ force 90hp

Took the boat for a test run today.

The boat is a Sliverline and is in good shape for its age. Been stored in a garage with a cover all the time.
The motor runs good, I played with a lot of starts,stops and shifting in and out of reverse and forward. It was very smooth and got the boat up on plane real fast. Also it does not smoke at all.

The 7 1/2 hp trolling motor runs good and starts very easy.

It does not have an amp gauge for the big motor but I guess one could be installed to insure it is charging.

With a little cleaning and a wax job the boat would look much better

The model number on the motor is 908F90C and serial number is 024781 and I was told it was made by Mercury.

john from md · Jul 23, 2009

Re: Used Boat ^ force 90hp

You don't need an ampmeter. Just add a cigarette lighter type outlet and use a plug in voltmeter from Walmart (< $20). This will allow you to plug in a voltmeter, inverter, cell phone charger etc.

Enjoy the new boat.

John

dblank · Jul 25, 2009

Re: Used Boat ^ force 90hp

I'm also looking at a "96 Force 90. I want to use it mainly in salt water. Never owned a motor larger than a Suzuki 25 (great engine). The boat is larger than what I'm used to-17' Sea Pro. Have been told by my Mercury and Yamaha friends the Force will not do well in salt water. But they didn't give much better advice on fresh water but they said definitly no salt. The motor is very clean and runs well in the tank. It has been kept very well. Any suggestions if I do buy it and use it in salt?

john from md · Jul 25, 2009

Re: Used Boat ^ force 90hp

dblank,

Your friends don't know what they are talking about. I have been running Chrysler/Force engines in the Atlantic, Delaware Bay and Chesapeake Bay since the 70's and am still doing it with a '85 Force 85.

As long as you rinse them out periodically and properly maintain them, they will last a long long time.

John

dblank · Jul 25, 2009

Re: Used Boat ^ force 90hp

Thanks John,

Any suggestions concerning maintenence will be appreciated. It is a Force by Mercury motor. Does that mean many parts interchange with Mercury? Also what type of oil do you recommend? I have no idea how many hours are on the engine.

Thanks

john from md · Jul 25, 2009

Re: Used Boat ^ force 90hp

The 90's series engines went through changes when Merc bought Force. The good thing about it is that there are more parts available for the later engines.

As far as oil goes, I always use Walmart Marine 2 stroke oil. It is made to the same standard, TCW3, and is alot cheaper than Quicksilver etc.

For you guys with recently purchased boats, if you don't know when your water pump was changed, change it now and then every 3 years for fresh and 2 years for salt water use. They only cost @ $25 and you don't want to wreck your boat for $25.

John

dblank · Jul 30, 2009

Re: Used Boat ^ force 90hp

Hi John,

Picked up boat Wednesday. Took it straight to the water. Ran it about an hour-idle and full throtle without any problems. 1 question- whats the switch on the left side of the forward/reverse control that can be operated when increasing power? It's a quicksilver control.

Thanks

john from md · Jul 30, 2009

Re: Used Boat ^ force 90hp

Can you send me a pic? There have been alot of different controls made.

If you can, send it to johnandnanc182@yahoo.com

John

mrwglo · Jul 30, 2009

Re: Used Boat ^ force 90hp

If it is on the inside (meaning left) of the throttle grip, it is very likely the powere trim/tilt button. Push up to trim up, down to trim down.

dblank · Jul 30, 2009

Re: Used Boat ^ force 90hp

Yes, thats what it is. A friend mine saw it and told me. The previous owner had installed a toggle switch below the key to lower the engine.

Thanks

Any suggestions on a mounted GPS that won't cost a fortune?

RGB5645 · Aug 1, 2009

Re: Used Boat ^ force 90hp

We have now our 1972 16 foot Silverline tri hull bowrider with the 90 hp Force
and it did need a new water pump which the owner had fixed and also a full tune up on the motor. The motor is a 1995 model and it does get the boat across the water in a hurry..

My main question is what it the best outboard oil and mix ratio to use with this Force motor,

Also came with nice Mercury trolling motor , fish finder and other items that one needs on the water.

This boat has been stored in a garage all the time and is in great shape for a 37 year old boat. Did order a new Bimini top for it as the old one was a little tattered.

Ray

john from md · Aug 1, 2009

Re: Used Boat ^ force 90hp

The oil mix is 50 to 1 which equals out to roughly 3oz per gallon. Buy one of those plastic measuring bottles from Westmarine or Kmart etc.

As to oil, if money is not object, you can buy Quicksilver or Pennzoil. If you are a working stiff like me, you use Walmart Marine two cycle oil, @ $11.00 a gallon vs $24 a gallon for Pennzoil.

John

dblank · Aug 3, 2009

Re: Used Boat ^ force 90hp

Hello John,

Used boat this weekend. 2 things-Motor bogs when accelerating. I had to slowly, and I mean slowly push the throttle. The front of the boat comes up high but hardly moves. When I pushed it too fast the motor would seriously bog. also twice the unit seemed to flood out easily when starting. Twice had to sit for a while after it did not start on the first kick. Do you think I need a carburator rebuild? I think it has the original prop and I'm not sure the pitch. Only had 2 other people onboard adding about 250 lbs. Did not matter if they were in the front or rear of the boat.

Thanks

john from md · Aug 3, 2009

Re: Used Boat ^ force 90hp

Check your plugs. I am willing to bet they are black and oily. Give them a good cleaning.
I would also check your mixture screws to be sure that they are no more than 11/8 open. It sounds like your mixture is too rich. Have you done a decarb on this engine? If not, it may be worth it to clean out some of the carbon and varnish in the system.

John

dblank · Aug 6, 2009

Re: Used Boat ^ force 90hp

John,

Do you know if these engines charge the battery when running? I had a saleman today at a boat shop that the engine has a built-in charging system but I see no indication of that. But I do have an amp gauge on the dash.

john from md · Aug 6, 2009

Re: Used Boat ^ force 90hp

You have an alternator under your flywheel. It consists of the stator and the rotating magnet in the flywheel.

Part of the stator is a charge coil. The magnet in the flywheel rotates around it and makes an AC current. It then goes to a rectifier or regulator depending on the model and year of the engine. The rectifier changes the AC to DC but does not regulate. It is not unusual to get 16VDC out a rectifier. The regulator will hold the voltage to 14.5 volts usually.

You can check the wires at the rectifier/regulator for output with a Volt meter. The yellow wires are AC and the Red wire is DC.

With a rectifier, you will need to get to 2000-2500 rpm to see a voltage rise.

John

Used Boat ^ force 90hp

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