1995 Force 120 Wont start, or crank with sparkplugs installed??

[Axi005]

Hello I am a new boat owner and am having a few issues with my 1995 force 120 Motor. I started it a few days ago on hose clamps and it idled fine. Today I went to start it and it wont crank over. It seems like there is pressure build up inside the motor and the exhaust valves arent opening? When I remove the spark plugs and the motor isnt under load it cranks over perfectly fine. What could be the problem

I checked-
Gas flow good with fresh gas and stabilizer.
New Battery, Tested battery today its at 92%
Cleaned all wire connections at all relays and at all terminals and battery cables with Dremel.
Oil level was checked and is good.
Spark plugs Tested and they all spark on each wire.


So the problem is the motor wont crank over with the spark plugs installed. what could be the issue? First thought was battery but its new and tested, Starter spins good with no plugs, Could it be exhaust related that its building to much pressure inside?
Thanks for all the help in advance.

 

[Jiggz]

Re: 1995 Force 120 Wont start, or crank with sparkplugs installed??

I understand you already cleaned the connectors and cabling as you mentioned. The next thing to do is to test the starter by jumpering it straight to the battery. I mean the negative on the body or the starter and the positive on the positive terminal, directly. If it still would not crank over, it could be a bad starter. I know it spins without load but that is not telling the starter is not bad. You might want to do a clean and inspect of the starter.

 

[jerryjerry05]

Re: 1995 Force 120 Wont start, or crank with sparkplugs installed??


Pic 1 is a tool I made to help install the brushes.
The next ones are from a supposedly working but weak starter.
The one of the brushes locked in the base,they aint supposed to be locked in place.
It's supposed to have pressure build up.
That's called compression, without it the motor won't start.
There are no valves in a 2 stroke.
Take the starter apart and clean it.
The brushes should float in the holder.
You've already cleaned the contacts, you do the grounds too?
Then do a compression test.
Fill out the profile,location?
You might be close to someone who can help.

 

[batman99]

Re: 1995 Force 120 Wont start, or crank with sparkplugs installed??

For my Force 120…..
- Replaced its thin factory #4 Gauge battery wires with much thicker #2 battery wires.
- On battery, now use battery "terminal post" instead of factory bolt with butterfly nut.
- Bought / installed 2.5 Amp Solar Panel from local WallMart/K-Mart store. When boat is stored or being towed, I ensure its Solar Panel "trickle charger" is connected (and facing the sun rays). Thus, ensuring the battery is fully charges.
- Clean inside of starter and ensure its wires & brushes look great. One my boat, its starter brush was worn down. Simply order starter brush kit ($35) at my local boat store. Much less costly than a brand new starter replacement. Jerry is showing some great starter inner pictures within his post.
- Remove all battery cable contacts, starter cable contacts and solenoid unit contacts, apply dielectric grease, then re-installed. Thus, getting better connection across their different metals.
- Use larger #27 (instead of factory #24) Marine / RV Grade battery. re: EverStart Marine Battery 27DC-850N

For winter storage months, I remove battery and store (on wood boards) inside my basement storage room. And, connect trickle charge every month for 48 hours. Thus, ensuring its fully charged during its winter storage months.

If wondering, I get the impression the Force 120 stator & regulator doesn't produce enough battery "charge power" under 1,800 RPMs. Thus, when on land, I use 2.5 Amp solar panel as a trickle charger. For this, I simply hard wire to battery posts and when solar panel is needed, I simply connect its wire cord joiner. Then, hang solar off boat's rear side. Or, lay on the flat floor when towing.

After applying above, all works great. Never had battery problems again. ALL these items might work for you as well… Especially remove, clean and inspect its inner starter brushes. Starter inner brushes tend to wear out in 5 - 8 years - like brake pads on a vehicle / trailer.

 

[Axi005]

Re: 1995 Force 120 Wont start, or crank with sparkplugs installed??

Thank you for all the help and advice, I apologize in advance I forgot to mention, I took the starter apart as well, it seemed pretty clean, I went through sanded down any metal contacts, sanded and degreased the magnets " 400 grit so its pretty smooth" i saw that the main (positive current bolt" was grounding so I put a plast washer on the outside with a sleeve going in to insulate that bolt going to the positive magnets, greased the main shaft where it seats into the bottom, So as far as I can tell the starter works good? is there any way of testing it directly under load with a volt meter? I also got jumper cables and ran them straight from the battery to the starter, same results it would not crank over. I greased all motor electrical connections with electric grease after I dremel cleaned them.
As far as the battery goes, its new Super Start marine battery 575 amp from Orielly. I used it so I cant return it for a higher amp battery.

Like I mentioned with the spark plugs in the motor wont crank over with the starter, once I unscrew the spark plugs it cranks great.
Also when I thought the starter was bad I would pull start it, and it would start. Now it seems like there is alot of pressure buildup inside the pistons and i cant even hand start with a rope.

So it appears to me with the spark plugs installed the compression or pressure inside the chamber is to high. To me it seemed almost like a clogged exhaust or something wasnt allowing the pressure to leave the chamber? Is that possible, could the pistons be getting stuck?
Like i said im new with boats and outboard motors in general so any help, tips or advice is appreciated.

 

[Jiggz]

Re: 1995 Force 120 Wont start, or crank with sparkplugs installed??

Thanks for the detailed updates. Another optio to try before further troubleshooting, try paralleling a second battery using jumper cable. If it still won't crank over then it is time to troubleshoot further. Now for the troubleshooting part. You suspect it is due to high compression but I say it is probably more of a binding. To find out which part, you have to do a process of elimination. Drop the lower unit and then try cranking it over again. Just make sure the shut down switch or lanyard switch is activated to prevent it from actually firing and running without cooling water. If it cranks over, investigate the LU. If it won't crank over still, remove the head, open and inspect the pistons and cylinders. Repost back what you find out.

 

[Axi005]

Re: 1995 Force 120 Wont start, or crank with sparkplugs installed??

Just wanted to update you guys. I think I found the reason, The previous owner loosened the clamps on the gas tank, when it rained the other day water went into the gas tank. Resulting in water and gas entering the combustion chambers. when I unscrewed the spark plugs i noticed some moisture on them, on further inspection i found the bottom two cylinders had a little water in them causing what I believer hydro lock. I flushed the gas, pulled the plugs, im allowing it to air dry with the assistance of a heat gun turned on low. After a few hours ill take a pipet add a few drops of oil into each cylinder and will hand crank it. I have my fingers crossed I hope that didnt damage the cylinders or the compression.

 

[Axi005]

Re: 1995 Force 120 Wont start, or crank with sparkplugs installed??

Thank you for all the help, I started the motor and had it run for a minute before I turned off.
I had to manually hand start it with the rope as it seemed the starter didnt have enough power to crank over even when I connected a battery directly to it. Would you guys have any recommendations on where i can purchase one? I heard eBay starters tend to fail prematurely. Im on a budget but I want to replace the part with something legitimate.

 

[Jiggz]

Re: 1995 Force 120 Wont start, or crank with sparkplugs installed??

Actually those Chinese made at Amazon or Ebay are not really that bad for the price. I mean for less than $100 it sure will last at least 5~7 years which is not bad at all. However, have you tried paralleling a second battery with jumpers just to make sure it is not a battery problem rather than the starter? I would especially if you are on a budget. Just use your car or truck battery nothing special is required.

 

[jerryjerry05]

Re: 1995 Force 120 Wont start, or crank with sparkplugs installed??

If you need to add a second battery or use a battery cable bigger than a 4 or a battery bigger than a 450cca then somethings STILL wrong??
Check the cable make sure it's not got a bad spot.
Check the grounds?
You gotta do a compression test.
The thought it has too much pressure is way off.
It should have at least 145# or more(depending on the gauge).
If 1 piston has low comp it will do what you are experiencing.
Water in the gas? It would have to be pretty much straight water to cause hydro lock.
Profile? Location?
The rebuild kits can be had at any Mercury dealership even e-bay.
A bad head gasket will allow water in the pistons and cause hard starting.

 

[Axi005]

Re: 1995 Force 120 Wont start, or crank with sparkplugs installed??

I actually did take a Good Bmw battery with around 800 cranking amps, and directly connected it to the starter with the Marine Battery hooked up to the cables and it still seemed like it didnt have enough power to crank over. But I can manually start it with a pull rope.
So im leaning towards it being the starter even though I took it apart, thoroughly cleaned all the bushes and metal components, and everything looked intact with the magnets at about 70%. Ill need to Check the compression and get back to you guys. Ill keep you guys updated when I have more time to work on it.

 

[Jiggz]

Re: 1995 Force 120 Wont start, or crank with sparkplugs installed??

Well, in that case I agree it is a starter problem. Sometimes the problem with starters is not obvious especially if it is a shorted winding in the armature. You will need a growler to diagnose such. Anyways, if you can pull start it but the starter cannot and after jumpering it I say it is a starter problem.