I just picked up my first boat with Force 120

I just brought home a 97 Maxum with Force 120 on it. Now What should I check for? I will be running a compression test to make sure pistons are good. Maybe do a tune up and rebuild the carbs and what about lower end, I dont know If there is any way to check for oil and stuff? Can someone fill me in a little bit? Old owner cranked it up in front of me and it started right up. A lot of white smoke so its oiling good. He shifted forward and backwards and saw the prop spinning and balanced. I just dont want my first time out to be a nightmare you know. Any help and advise will be greatly appreciated guys.

Re: I just picked up my first boat with Force 120

A compression test to guage the health of the motor is a good idea. Change the lower unit oil, water pump impeller, and fuel pump diaphram, as all are cheap and mission critical.

Now, go to Wal Mart and buy the biggest tote they sell, it's the only thing I've found that fits these monster lower units. I rigged some plywood and ratchet straps to keep the sides from bulging out. Put it under the lower end, fill it up with water, and let it run at a high idle for as long as it takes to convince you that it's reliable. Don't put it in gear at anything but minimum speed or you'll end up with an empty tote and a big puddle (ask me how I know). If it seems to behave itself, runs smoothly, doesn't overheat, I wouldn't bother with rebuilding the carbs, maybe just pull the float bowls and clean them out.

Re: I just picked up my first boat with Force 120

checking lower unit gear lube is the same as changing it. You need a pump (about $7 at walmart) and some new gaskets. (any mercury dealer has them and they are cheap). remove all three plugs, one on the bottom of the torpedo, two on the side and drain. Look for water and indications of water such as milky looking fluid, metal shavings would be bad also. refill with the unit trimmed down. Pump from the bottom (one quart should be plenty) until it comes out of the holes at the top, and replace plugs and gastkets to both. unscrew the pump and put the last plug in the bottom. make sure you use a big enough screwdriver so you dont mess up the plugs when removing/installing. hope this helps!

Re: I just picked up my first boat with Force 120

Just look over everything very good. like all wires, gas lines, and make shure everything is gressed and oiled good. I would let it run a good while at home with the cover off and just look and lisen to the motor.

Re: I just picked up my first boat with Force 120

Too late now but you should ALWAYS at least run a compression check BEFORE buying a used motor.

Re: I just picked up my first boat with Force 120

The thing is; Old owner listed this bowrider sunday night for $2500. I checked the nada value and it showed $5150 so I called them up and asked him if it was running good and he said he barely used it since brand new, it was just sitting and he wanted to get it out of his yard. so I went there he bought a new battery cranked it and it started right up. At that point I asked him to give me a deal and we finished it off at $2000 which includes a 97 trailer and a 97 maxum 19 feet bowrider and a 97 force 120. So I didnt want to go ahead and jinx him off while his phone was getting a call every minute or so about the boat. Engine seems clean, I will start digging into it tomorrow.Will check the compression first then run it for a while on the hose and see how it idles and stuff and check the lower unit oil. Does this thing have a water pump or is it driven by the prop?

Re: I just picked up my first boat with Force 120

Don't see deals like that everyday. Good score!!

Re: I just picked up my first boat with Force 120

It has a pump it's on the drive.Get a manual.A factory is best Clymer is OK.
Boats.net Has your motor listed.Go ther pull up gear housing and look for the pump.
You should have a water/fuel seperating filter.Or an in line filter.
Ethanol is in most fuel and messing up lots.
Regular maint:additives for ethanol, keep the oil in the lower filled.Drain it from the bottom and fill it from the two holes on the upper end.I fill it till it comes out one hole.Then fill from the other hole till it comes out the other side.Then do it again.Keep a set of spare plugs in a tool box.When you get the manual.READ IT.Lot's of valuable info there.J

Re: I just picked up my first boat with Force 120

OK here it goes, Pistons from top to bottom 135psi there are small variances like 136 or 134psi, but in general they are all over 130psi. So I assume these readings are ok. Spark plugs were all clean except top one, it had a black residue (carbon build-up maybe) it might be running a little rich or not firing good. I will put a new set of plugs ( please advise on brand and model) Checked the lower end oil, color is like a brand new motor oil. No metal shavings or milky oil. I will still go ahead drain it and refill it. So far so good. When I hook up the garden hose I didnt get any water from pee hole. Is there a thermostat on this thing? Gas filters look clean and I can see there is a good flow, Looks like fuel pump is doing its job. I cant really tell anything about the carbs without launching this thing because its hard to do a judgement in a garage.
Guys I really appreciate all the ideas and advises you provide.

By the way can anyone break down this serial number for me?
Its OE246364 Its a 97 120hp. I need to know if this is the 3 jaw or 6 jaw lower end and is it Long shaft or short shaft. I know I am asking a lot of questions sorry.

Re: I just picked up my first boat with Force 120

The shaft length is measured at the transom.The top/center of the transom to the bottom of the v.Should be around 20 or 25 in.
The hose might not supply enough water.Tape it on and use lots of tape.
Otherwise put it in the water.A piece of weedeater string in the pee hole will keep it clear.
Compression sounds good.Oil sounds good.
Can't help with the 3 or 6 jaw. Why do you need this info?
Put in the same plug that you pull out.They all work.Buy American if possible.
The worst thing for an outboard is letting it set.Stuff seems to go bad that way.J

Re: I just picked up my first boat with Force 120

Go to this link to determine how many jaws:
http://www.crowleymarine.com/mercury-outboard/parts/2009_180.cfm

PS. I have also got the 1997 Maxum 17' with Force 120 for $4000 a month ago

Re: I just picked up my first boat with Force 120

Thanks anple.I just learned something today.J

Re: I just picked up my first boat with Force 120

1997 Force 120 should be 3 jaws. 98-99 is 6 jaws.