25/20 jet starting problems

[rgmatt]

Hello to all,

first alittle history on the motor

I have a 2005 merc 25/20 jet. The motor came as a manual start and I had it rigged for remote controls/electric start from the dealer. Everything was fine for the first year and a half. Then I had a start solenoid go bad. Dealer replaced it and 2 weeks later, it started acting up again,dealer replaced again free of charge. 2008, starter goes bad and I take it to a different OB tech (I had little faith in original dealer by now). Replaces starter and goes over all wiring. First trip out starter starts acting up and it tests out as a bad starter. Replaced again. Late last season I had to replace starter and solenoid again. While I was at it I replace d batt., batt. cables and a few other wires for the system. Thurs of last week I have the boat out, starts fine all day, back the trailer in the water, go to drive on the trailer, nothing but a clicking solenoid. Try to jump the solenoid, NADA.

So I went over the simple stuff this weekend, battery, batt. cables fuses, and replaced the solenoid w/ a new one I had as a backup. The wiring harness from the controls is good , I've been using a short keyed harness at the motor to test everthing. Tested it per the merc manual and it's coming up as a bad starter. I did find a small spot on the harness in the motor w/ what looked like a melted spot, there was elec. tape over it and I didn't notice it till now. looks like this could be it and I'm ordering another one.

BUT

any other things I should be checking here. I'm no mech., obviously. Would a bad rectifier cause some of these ongoing probs? Battery stays charged though.

thanks in advance
Matt

 

[TwoFish]

Re: 25/20 jet starting problems

Hi Matt

You certainly have had a run of problems! You have gone through the system & replaced/checked a lot of the common likely faults. I?m no expert but I cant see the rectifier causing the problems you are having if the battery is staying fully charged. You could try charging the battery overnight and seeing if this makes a difference.

The easiest way I know to test a starter is to use a set of jumper leads. Disconnect the main cables from the battery. With the jumper leads connect the positive battery terminal to the positive stud on the starter. Then connect the other jumper cable to the negative terminal on the battery and then touch the other end of the jumper cable to the casing of the starter. Be careful of moving parts and sparks. If the starter works OK we need to trace back through the starter circuit.

Have you noticed any change in how fast the starter turns the motor over when it has been working in the past. Just trying to get an idea of whether the problem is something that degrades over time.

Cheers

Dean

 

[rgmatt]

Re: 25/20 jet starting problems

Other times the starter and or solenoid have shown signs over time. This past Thurs went from working 100% over 9 hrs of fishing but after a long run up river, wouldn't do a thing. Something heated up? Also this isn't the first time this season it's been used, probably the 6th and another dozen trips from last year after the starter and solenoid were replaced. Worked 100% in all those trips w/ No warnings. Motor did start by the manual pull start BTW.

As for the rctifier, I can't see how it would be the problem either as the batt. stays w/ a good charge. Batt. tested 100%.

 

[TwoFish]

Re: 25/20 jet starting problems

Have you tested the starter with the jumper leads?

Does the system work when things cool down? Next day?

When you bridged the solenoid the other day which contacts did you bridge? A - B or A ?C?
Your solenoid my have a different configuration to this drawing. The heavy terminals will be the positive in and out. The smaller ones will be earth(black or green) and positive from the switch ( yellow/red possibly. I don?t have a wiring diagram for your motor).

As for the idea it may be heat related this is one possibility. It could be what is called a voltage drop. It can occur on the main power leads or the starter switch circuit. You have changed the main leads so they should be OK. The wires on the switch circuit can corrode or the switch can wear, resulting in poor current flow to the switch side of the solenoid. The current carried by the wire may be marginal but still able to work the solenoid. When the wire heats up it cause more resistance in the wire and can no longer carry enough current to work the solenoid. I had a car that did this on really hot days (100 degrees +). It would work again when things cooled down. Changed the starter which looked like it fixed the problem until the next really hot day. Finished up having an auto electrician fit a $10.00 relay which fixed the problem.

Post the result of the test and we will go from there.

 

[rgmatt]

Re: 25/20 jet starting problems

I have not tested the started w/ jumper yet, just a meter.

It does not work after a cool down period.

tried bridging both to jump the solenoid; first A-C and then A-B

thanks for the help
Matt

 

[james79]

Re: 25/20 jet starting problems

i had the same thing happen to me in it was the rectifier

 

[TwoFish]

Re: 25/20 jet starting problems

Bridging from A-B eliminates the solenoid. Does the starter move at all when you bridge the solenoid?

Can only be starter, wires or battery(low on power for some reason).

The next thing I would do is to is to use the jumper leads to eliminate the wires. This just leaves the starter or the battery. Only do this for very short periods. Look to see if the starter tries to move or makes a noise at all. If you have another battery around you could use it to test the starter if the starter is not working with the first battery. You could try charging the battery overnight and seeing if this makes a difference. As James79 indicated the battery may not be charging properly. You never know.

Have you had the battery load tested? If you haven?t it would be interesting to see what the results are. As far as I know a battery can show 12 volts if read by a volt gauge but still fail when under load. I know it is new but it would rule out one suspect.

Post your result and we will go from there.

Good Luck


James79. When you had a rectifier problem did the battery loose power and cause starting problems through lack of power to turn the starter?

 

[rgmatt]

Re: 25/20 jet starting problems

James79, I like to hear some more details on what was happening when you had a bad rectifier as well

2fish,

load tested the batt and it came out good to go

had the shop down the road test the starter and it's shot. He opened it up and said it was poorly built. I had the other starter at home and opened that one up too, both had the wire windings come loose and look to be arcing.

So starters shot, solenoid is good, but I'd hate to put another starter in and have it go in another 6 months. It's crazy how many starters I've had in this motor (this will be #5 on a 2005 motor) if I put a new starter in, it will start, but for how long.

any reccomendations on where to buy a starter. The ones from merc didn't seem any better or last much longer. This last one was off the net.

any thoughts?

thanks again
Matt

 

[TwoFish]

Re: 25/20 jet starting problems

I?ve never had to buy a starter so I?m no help there.

You have done well tracking the problem down.

As far as what is causing the problem it is outside of my knowledge unfortunately. I could have a couple of guesses but they would only be guesses.

As you were saying earlier my hunch is that it is heat related.

In the past before you changed the cables & battery the power to the starter was low and allowed the starter to sit in one winding or turn slowly heating up more than turning and burnt out a winding.

If your motor is hard to start and the starter is used longer than 10 or 15 seconds at a time for extended periods without letting it cool of a couple of minutes between starts it can heat up very quickly causing the windings to fail.

The gear on the starter is binding on the flywheel causing the starter to heat up. You would see marks on the gear if this was happening. Unlikely all 5 would do this.

Hopefully James79 will have the answer.

If you have a motor rewind shot near you they may be able to give you an opinion.

Did the mechanic have any suggestions?


Good Luck

 

[rgmatt]

Re: 25/20 jet starting problems

As you were saying earlier my hunch is that it is heat related.

In the past before you changed the cables & battery the power to the starter was low and allowed the starter to sit in one winding or turn slowly heating up more than turning and burnt out a winding.

If your motor is hard to start and the starter is used longer than 10 or 15 seconds at a time for extended periods without letting it cool of a couple of minutes between starts it can heat up very quickly causing the windings to fail.

The gear on the starter is binding on the flywheel causing the starter to heat up. You would see marks on the gear if this was happening. Unlikely all 5 would do this.

Hopefully James79 will have the answer.

If you have a motor rewind shot near you they may be able to give you an opinion.

Did the mechanic have any suggestions?


Good Luck

One of the starter failures was most likely caused by a weak batt. but not the 4 others as it's been something I've been watching since.

Motor starts right up first try when starter is working properly, one turn of the key. BUT this is a shallow rocky river boat and b/c of the conditions and flowing water, chutes in between pools are sometimes very quick drifts, I tend to start the motor more times a day then say a guy out on a lake. The motor might get started 30 plus times an outing.

I did notice some wear on the geared flywheel but I believe this from one of the other starters that went bad, it had "hot spots" where I to tap on it a few times to get it working. (I've been pulling out alot of "on the water fixes") one time a bolt actually loosened up and thats wear the gears didn't mesh and marked up the gear. I've also checked this w/ the other starters to see if the gears were engageing right.

AS far as the shop I stoped by today, they specialize in auto elect., starters and alternators. The owner helped me out and his opinion was that solenoids don't just go bad and when they do it's usually batt. related, and the starter I had was cheaply made china crap, but that's mostly whats out there. I'm going to get a part # for him and see if he can get me something better. From the looks of this last one it does look like it could have been poor quaility. just makes me nervous and I've actually consindered ripping the whole thing out and pull starting the damn thing from now on. Sucks though since it's a stick steer in the front of the boat.

Matt