98 force 120 - random starting issue

[ky_boater]

Its been a while since I've been to the boards, but have been running into a random issue since the end of last summer with the boat and figured I would try iboats.

I have a 98 Force 120 that when starting will act as if the battery does not have enough juice to crank the motor. I turn the key and it will make a slow crank sound once or twice then nothing. I will give it a few minutes and then it might fire right up or at least crank the motor trying to start. Once it is started the issue does come back, sometimes it will fire right up and then the next time I try to start the motor it will do the slow crank.

Last summer when it I first started noticing this I would swap out the battery with another and that wouldn't fix the issue (I also bought a new battery just to be sure). I did notice on the starter relay that the plastic shielding that is over the bolt / cable going to the battery was melted. I moved that cable around a little bit and then tightend the nut on the starter relay just to make sure there was a good contact and that seemed to fix it, or so I thought.

I took the boat out last week and ran into the same issue right from the start. I cranked it a few times and it did the real slow crank like the battery was out of juice even though I had just finished charging the battery. I proceeded to pull the cover off the motor and was going to check to see if the cable going to the relay was loose again. When I grabbed that cable I nearly went into the water as it was extremely hot. I only cranked the engine 2 or 3 times before checking this. I then let the motor sit for about 10 minutes. I turned the key on the motor and could here the relay clicking and the motor was now trying to start and not doing the slow crank. I was able to get the motor started and from then on ran fine the rest of the day. I am wondering if the relay is going bad or sticking causing a short or something like that.

Appreciate any advice.

Thanks.

 

[SweeperForce]

Re: 98 force 120 - random starting issue

The first thing I would do is check your battery and ground connections, make sure sure they are all clean and tight. No rust or corrision should be persent at the connection site. Second, make sure or upgrade your wires. My boat came with 10 gauge I pulled all if it out and replaced with 4 guage marine battery wire. It make a bigger difference.

Hope this helps,
Tom

 

[Lone Duck]

Re: 98 force 120 - random starting issue

After checking all wires & clean grounds, use jumper cables and jump directly to starter. Do it 2 or three times with 5 min waits in between jumps. If it spins over like it should, then the problem is in the wires or solenoid. If it does not then you need a new starter and possibly a new solenoid.

 

[Frank Acampora]

Re: 98 force 120 - random starting issue

The armature of the starter has very heavy windings. The wires are almost a eighth of an inch thick. When the starter turns slowly, no back EMF is generated to resist current flow and massive amounts of amps are drawn from the battery. That is why the wires heat to the point of melting insulation..

SO: It is not a battery problem. More than likely, the springs that hold the brushes in contact with the copper commutator are overheated and it no longer makes good contact with all four brushes. It is time for a rebuild or a new starter.

Background: When an electric motor is energised, there is a heavy current draw at first start, Then, as speed picks up, the armature windings spinning past the magnetic field also generate a voltage the reverse of battery polarity. This is called back EMF and serves to effectively limit how many amps the motor will draw while running. Thus, if an electric motor is operated at stall, full current will flow and if kept for a period of time will melt insulation on the battery wires and also the armature windings, destroying the armature.

 

[jerryjerry05]

Re: 98 force 120 - random starting issue

Try a compression test?
Sometimes low compression on 1 or more cyl. will cause it to turn over slowly.
It's 15 years old, is it the original starter?
Take it apart and check the brushes?
Like the others suggest, connections?
Profile? Location? You might be close to someone who can help.

 

[ky_boater]

Re: 98 force 120 - random starting issue

Thanks for all the replies. I will check the connections again tonight for rust, looose, etc.. but I believe those are okay. The starter has never been rebuilt as far as I can tell. I bought the boat/motor in 2006 from the original owner, so I'm not 100% sure.

Also, I am in Northern Kentucky and will update my profile.

Thanks again. I will keep you posted on the results / findings.

 

[ky_boater]

Re: 98 force 120 - random starting issue

I checked the battery connections and those all appear to be good. As far as the starter, if I take it apart is their anything in particular to look for to determine if that is the issue. It was mentioned above "the springs that hold the brushes in contact with the copper commutator are overheated and it no longer makes good contact with all four brushes.", would this be noticable when taking the starter apart?

I will probably just order a new starter, but would like to try a few things if possible.

Thanks again.

 

[Lone Duck]

Re: 98 force 120 - random starting issue

I checked the battery connections and those all appear to be good. As far as the starter, if I take it apart is their anything in particular to look for to determine if that is the issue. It was mentioned above "the springs that hold the brushes in contact with the copper commutator are overheated and it no longer makes good contact with all four brushes.", would this be noticable when taking the starter apart?

I will probably just order a new starter, but would like to try a few things if possible.

Thanks again.

Do the jump test first.

 

[jerryjerry05]

Re: 98 force 120 - random starting issue



Don't just throw money at it!!!
The starter's easy to check. Look for dirt and corrosion.See pics.
The one is a brush holder for reassembly.
Try taking the plugs out and turning it over.
If it turns easily then you should really do a compression test.

 

[ky_boater]

Re: 98 force 120 - random starting issue

I tried to reply earlier but I had issues pulling up the site... Either way... Last night I pulled the starter off the motor and was able to hook it directly up to the battery. The starter popped up and spinned with no issues. I then put the starter back on to try and "jump" it. Before trying that I turned the key to test it and the motor had no issues. It was cranking the motor everytime. I then waited about 20 minutes and again no issues. Before leaving for work this morning I tried it again and again no problems cranking the motor.

I am thinking that pulling the starter off and moving / banging it around freed in the starter ??? and possibly fixed it temporarily. Would you say this clarifies the issue definitely being with the starter?

Thanks for the posts / pics jerryjerry05 and Lone Duck

 

[Lone Duck]

Re: 98 force 120 - random starting issue

I tried to reply earlier but I had issues pulling up the site... Either way... Last night I pulled the starter off the motor and was able to hook it directly up to the battery. The starter popped up and spinned with no issues. I then put the starter back on to try and "jump" it. Before trying that I turned the key to test it and the motor had no issues. It was cranking the motor everytime. I then waited about 20 minutes and again no issues. Before leaving for work this morning I tried it again and again no problems cranking the motor.

I am thinking that pulling the starter off and moving / banging it around freed in the starter ??? and possibly fixed it temporarily. Would you say this clarifies the issue definitely being with the starter?

Thanks for the posts / pics jerryjerry05 and Lone Duck

One of two things, either you had a bad ground or power connection to the starter, or you have knocked the brushes back in contact. You have the choice to run it like that and hope it is fine. Or pull the cap off and check the brushes. I would order the brushes then pull it apart.

 

[jerryjerry05]

Re: 98 force 120 - random starting issue

Yup,take it apart. The brushes and armature can be corroded.
Sounds like a bad connection.

 

[foodfisher]

Re: 98 force 120 - random starting issue

Mounting to the block is a ground connection. You may have reestablished that ground.

 

[ky_boater]

Re: 98 force 120 - random starting issue

Sorry for the delay on this, but finally got around to pulling the starter off to make the repairs. When taking the starter apart and pulling the ends off, I did notice a burnt smell. I attached some pictures. Let me know what you guys think.

Thanks.

 

[ky_boater]

Re: 98 force 120 - random starting issue

Related to the brushes. I noticed that the springs were extending out of 3 of the 4 brushes. As you can see in the 3rd picture, one of the brushes is just sitting in the slot and not being pushing out. Do all 4 of the brushes need to always be making contact with the other side? I'm wondering if the spring on the one not pushing out is bad.

Thanks

 

[ky_boater]

Re: 98 force 120 - random starting issue

I cleaned the end of the starter (the copper part) with a dremel. That took a layer of black stuff off and shined it up. I then put everything back together and hooked it up. The motor still tried to crank real slow and could then hear the relay (i think it was the relay) making a fast ticking sound. Must be something I missed in the starter (possibly the brushes or something to do with those)

 

[Lone Duck]

Re: 98 force 120 - random starting issue

I cleaned the end of the starter (the copper part) with a dremel. That took a layer of black stuff off and shined it up. I then put everything back together and hooked it up. The motor still tried to crank real slow and could then hear the relay (i think it was the relay) making a fast ticking sound. Must be something I missed in the starter (possibly the brushes or something to do with those)

Make sure the slots between the ends of armature where you polished are clean with no filings or carbon dust between them. also were you able to free up the one positive brush that was stuck? (the brushes with wire bolted to starter are the negative brushes) Is the positive terminal where the solenoid wire attaches tight and insulated from starter body? Lastly a clicking solenoid usually means not enough voltage to turn starter, poor connection or battery.

 

[ky_boater]

Re: 98 force 120 - random starting issue

Lone Duck,
you were right... the battery was dead. I put another battery on the motor and it cranked. I am hoping the stuff I cleaned off the starter was the initial cause of the starter not cran.

 

[Lone Duck]

Re: 98 force 120 - random starting issue

Lone Duck,
you were right... the battery was dead. I put another battery on the motor and it cranked. I am hoping the stuff I cleaned off the starter was the initial cause of the starter not cran.

Glad I could help. Where you able to free up that stuck brush? I think that was most of your problem,along with the batt.

 

[jerryjerry05]

Re: 98 force 120 - random starting issue

The brushes actually looked ok.
You can take them out and try turning them over.
A wire brush on the housing(gently)and then soap@water.
Blow dry and reassemble.
The one not comming out of the slot could be a problem.
The rebuild kit is under $20 get one and replace.Keep the old for spares.
The armature,check for a short.The end that's divided into sections.
Clean between the sections.Then an ohm meter.Check for continuity between the side and the end.
Make sure it's not shorted out to the other sections.
Reassemble and then check the battery leads.
ANY weak or corroded spots?
Then get the battery load tested.
I bought one from Harbor Freight,about 25$
Then do a compression test.
Make sure you remove all the plugs when doing the test.