Force 120 slow cranking starter

[mikemo1964]

Hello all. I just purchased a 1995 Maxum 1700 with a 1996 Force 120 outboard. I'm new to power boating so please forgive my ignorance. When I took my sea trial I noticed that when he started the motor it turned over very slowly, but seemed to start easily. It cranked like a car that had a nearly dead battery (wooh...wooh...wooh). I wasn't sure if that was just normal.

We took the boat out for the first time last Friday. We got it in the water and the motor started (the same slow cranking as before). We ran it for an hour on the lake and then headed back to the ramp. I wanted to test a hot-start, so I left it in the water for 5 minutes then tried to start it. It clicked but wouldn't spin. The boat has dual-batteries so I switched to the second. Same thing. When I switched to both I was able to start it, but it cranked very slowly.

I pulled both batteries, charged them then took them to the auto parts place to be tested. They both tested good with over 500CCA. I put them back in the boat and started it but had the same slow cranking symptom. When I replaced the batteries I cleaned the connectors and the battery terminals and put some dielectric grease on them.

The engine has about 250 hours on it. The PO had a receipt from a water pump and bottom end reseal from last year. The compression was tested at 135psi in each cylinder. The engine seemed to run perfectly while we had it on the water. WOT had the motor at about 5200rpm and 40mph indicated. It cruised at 30mph and around 4200rpm. (we had fun on our first outing, btw)

Is this just simply a bad starter? Any other tests I can run to isolate the issue?
Thanks!
Mike M.

 

[JSMoore]

Re: Force 120 slow cranking starter

Look for a bad ground, bad connection, or possibly a cable that's got "black wire corrosion" running up inside it. If you're not getting all those CCAs to the starter, it ain't going to crank over very well. Just a thought.

 

[Tattooduck101]

Re: Force 120 slow cranking starter

mikemo, i had the same click, ruf ruf ruf then start when i first got my 1990 maxum which has a 1990 120hp force. i replaced my batts, no good. i bought a merc repair book to locate grounds and its on the side with tilt trim relays. it was tight but where the wires crimp onto the connector under the insulation it was black, and had lots of resistance to batt negative. I replaced with new wire and connector and it starts much better. Its all about amps, you could have all the volts in the world going to the starter but with low amps she just wont turn. hope this helps.

 

[fucawi]

Re: Force 120 slow cranking starter

The fastest way to a solution is to measure the battery volts when cranking ..should be at least 11.5v and then the voltage at starter .. input bolt to casing ..should be at least 11v ....If not you have a bad connection ...could be a bad solenoid ( voltage across soenoid terminals cranking not over 0.25v )

Bad connections may get hot ...Charge batteries ..stand 24 hrs ..should be over 12.5v with no load otherwise suspect

 

[jerryjerry05]

Re: Force 120 slow cranking starter

Could be the original starter.Along with the other tests,take the starter apart.Check the brushes,make sure the magnets haven't broken loose.They are just glued in place.
If all that fails.Remove the lower unit and try to start it that way.J

 

[fucawi]

Re: Force 120 slow cranking starter

jerry jerry ...he said it starts easily so why would he take off the lower unit? If magnets have come unstuck it would be jammed solid .....dont understand your logic .

He could have a short in the starter ..normal draw about 150 A with a short 400A difficult to detect except if you remove the starter it still runs slowly rather then the 11000 (eleven thousand) you would expect

 

[bentle]

Re: Force 120 slow cranking starter

Is there any chance the fly wheel may be loose causing a bind between starter gear and fly wheel teeth. Also make sure your starter bolts are tight. If loose at all it will make the starter drag to one side or the other. If after cleaning starter out and testing it still drags then if you can? Just get a new starter and save yourself the headaches. Remember though you get what you pay for. I think what jerry meant to say was remove lower leg and try to turn motor over to rule out any prob. in the lower leg that could be binding up and causing starter to drag. Dont let the motor run though. It will overheat very quickly 15-20 seconds.

 

[JSMoore]

Re: Force 120 slow cranking starter

I vote for a bad connection or a corroded wire. I've never had the honor of owning a boat newer than 10 years old. And, one thing that has been a common fault in all of them is that nasty, creeping, black wire corrosion. Sometimes you can peel the insulation back 3 feet from the wire terminal and STILL find that black corrosion. It probably cuts the wire's conductivity in half. And, it gets worse when the wire gets hot.

Apply the "KISS" principle. (Keep it simple stupid). Start with your battery cables & work you way through the charging & starting system. If you find a "black wire", replace the wire. It can't be cleaned or repaired effectively.
Just my 2-cents worth learned the hard way.
JSMoore

 

[Jiggz]

Re: Force 120 slow cranking starter

My bet is on the starter but I would do a test by jumping it straight to either one of the batteries or maybe even on both using car jumper cables. If the starter still cranks slowly then it's without a doubt a starter that needs cleaning and a probably new brushes. If the starter cranks fast like a normal starter, then it's either a wire connection problem or the solenoid contacts partially worn out.

 

[fucawi]

Re: Force 120 slow cranking starter

yes and if the jump leads are thin craap then your test is a waste of time...checking flywheel turns by hand is a good idea

My policy is if its a new thread I will give advice ..if its gone to 8 or 10 then waste of time as there is so much bullshhit flying about you will never sort it out......

 

[Jiggz]

Re: Force 120 slow cranking starter

What about if the jumper leads are super heavy duty,4 gauge cable? Why would it be a waste of time when the test will surely eliminate the starter as either the source of problem or not? OK, so he turns the flywheel and it turns by hand? So is the starter bad? Solenoid? Well, with the bendix drive disengaged, I sure hope he can turn the flywheel by hand, albeit slowly. Remember the engine starts and run except that the starter cranking is slower than normal.

 

[jerryjerry05]

Re: Force 120 slow cranking starter

I'll do this again FucawAH I post from my experience.I list POSSIBLE problems.Instead of tell me I'm wrong try to use your energies in helping these peole fix their motors.
The lower unit could be binding and causing it to be hard to start.
My present boat,I bought it cause it was just like my other with twin85/s.
One motor would turn and start NO trouble the other needed 2 batteries to start.
I looked at everything,Twice.Even pulled the head to see nothing.Two starters later.
Then I dropped the lower unit and it started NO problems.
The lower unit upper driveshaft bearings were binding.
The magnets come loose in the housing. They don't automatically bind up the starter.
I have take them apart and found as many as three pieces on a starter that will turn,just slowly.

Like I said before,if you don't like what I post don't read it.You don't get to criticize here.
It's a help forum.
If you can help then help.AH.

 

[fucawi]

Re: Force 120 slow cranking starter

After 30 + years working on starters/batteries and the like my moto is Test dont Guess ..Every week I receive problems to solve from all over the world..many of the solutions are published and read by a readership of 80,000 . I am fully qualified as a fault finding expert on electircal and associated systems. I get many direct pms from people on this site and others so my advice is ..... .$10 spent on a digital voltmeter and follow the instruction from a professional is much better than "in 1989 I found the fault was this or that " you didnt you disturbed something as you messed with the system spent money on new parts and though you put it right with your new parts that were not neccessary..seen it 1000+ times
TEST DONT GUESS

a good starter will do 11000 rpm without load ( 2000 if its got a short)
a good starter will draw 40 A without load ( 400 A if its got a short )

Test to see if your motor is good or bad using the above informaton, If you dont have the equipment to test it go to someone who does ....

 

[mikemo1964]

Re: Force 120 slow cranking starter

Thanks for all the information guys. I have a volt meter and I will test the cranking voltage at the battery and at the starter. I also found a magnetic ammeter that is used for car charging and starting system. It is supposed to give you an estimate on cranking current draw and charging current. I'll check things out tonight and report my findings.
Thanks again for your time and assistance. It's nice to know I'm not alone.
Regards,
Mike M.

 

[fucawi]

Re: Force 120 slow cranking starter

good call mikemo

 

[Jiggz]

Re: Force 120 slow cranking starter

Just a word of caution. What Fucawi mentioned for test criteria are based on a direct, non-faulty wiring starter connections. If you have faulty, loose or highly resistive wiring connections (i.e., partially corroded solenoid contacts, loose or dirty ground connections or loose dirty hot wire connections)between the battery, solenoid and starter you could end up with a wrong diagnosis.

 

[mikemo1964]

Re: Force 120 slow cranking starter

Well, I got some data, but I'm still not positive what the problem may be.

Before trying to start, battery measured 12.7 volts.
-When cranking (or trying to crank) the battery voltage drops quickly to 10 volts. Starter spins partially then stalls.
-Voltage across the solenoid was about 0.2 volts while cranking.
-Voltage at the starter while cranking was near 10V at first, then quickly dropped to 8V when the starter stalled.
-I tried to use this magnetic ammeter, but I'm not confident in its measurement. It said it was only drawing about 100 amps while stalled. I don't believe that reading.
-Both batteries I tried were fully charged and tested at over 500CCA by the local autoparts store.
-After a couple of brief attempts, the bottom of the starter was beginning to get hot.
-I used a set of auto jumper cables and a fresh battery and directly connected to the starter. Same result, half a spin, then stalled.

I assume that to test the no-load rpm of the starter that I'll have to remove it from the engine. I'm not sure how I would measure the rpm though. I don't have an optical tachometer.

I suppose I could buy some new wire and connect a battery directly to the engine and see if things improve. Or maybe it's just time to buy a starter...

Thanks again for any advice.
Mike M.

 

[jerryjerry05]

Re: Force 120 slow cranking starter

You take it apart and look at the brushes?Take you 5 minutes.
All the technical info won't do anything if the insides need repair.
Bad brushes,loose magnet?Shorted armature?
.

 

[flightdoc]

Re: Force 120 slow cranking starter

Jerry jerry, have you not learned? Never argue with fucawi He is a chief petty officer on this site. I am in the navy and I know how chief petty officers are. they yell a lot (or all caps type) and they hate it if you don't agree with what they are saying or say anything to prove their knowledge wrong. I think the appropriate thing to do here would be to PM people so as not to **** Fucawi off.

 

[Jiggz]

Re: Force 120 slow cranking starter

Unfortunately, this is a public forum and everybody and everyone has their own opinions. If only they can contain it to themselves and their own posts we'll continue to make this forum civil and productive. Anyways, the starter is bad. Replace it or rebuilt it. The most likely cause is either the armature is totally shorted due to accumulation of carbon from the brushes wear, or the bearings are worn out which makes the rotor rides the stator. I'll go for a new starter personally. Rebuilt ones are cheaper but I'll never take a chance on a major part as significant as a starter.