1996 Force 90 hp starter/solenoid problems

[theforce]

I have a 1996 Mercury Force 90 hp. I have replaced the starter 3 times since April. Put a new starter on yesterday and it cranked fine the first time. Shut it down for a few minutes and hit the key again and the starter would spin but not engage the flywheel. Could the problem be a faulty solenoid? Someone PLEASE help.

 

[Barnacle_Bill]

Re: 1996 Force 90 hp starter/solenoid problems

The starter probably wouldn't work at all if the solenoid was bad. Is your battery fully charged?

 

[theforce]

Re: 1996 Force 90 hp starter/solenoid problems

Thanks for getting back to me. The battery is new and is fully charged. I think that there may be a bad spot on the starter shaft. Went to start it the other day and same problems, it turned but did not engage. I took a screw driver and gently lifted the the wheel. Turned the key again and it worked like a charm. could the be a small "spur" on the shaft causing this and if so, how do I fix it?

 

[lncoop]

Re: 1996 Force 90 hp starter/solenoid problems

Welcome aboard. Could certainly be a tiny burr or speck of something on the shaft that's preventing the bendix from spinning up and doing its job. I had this problem a couple years ago on my ninety horse Merc. When I got home from the lake I squirted one drop (yes, only one drop) of 3in1 on the shaft and spun the bendix up and down several times by hand. Haven't experienced the issue since. BTW, probably doesn't matter much in this case, but if you have other issues you should probably post them in the Force section. Some issues are brand specific. Good luck.

 

[New.boater]

Hi there,

I have the same problem with my 1995 force 90. The starter spins but does not jump up to engage the fly wheel. Should I just put some WD 40 oil around the starter and see if the starter would loosen up and jump to engage the flywheel?

When you said you used a screw driver to lift the starter-would it just lift with some help?

Thanks,
New.boater

 

[pnwboat]

There are a couple of problems that could cause the bendex gear on the starter not to engage.

1. Bad bendex assy.
2. Debris or corrosion on the bendex shaft. Clean and lubricate. Just a small amount of lubricant, don't over do it or it will attract more crud.
3. Starter not spinning fast enough due to bad starter, bad battery and or corrosion on the battery cable connections. Also a bad starter solenoid (pitted, burned internal contacts).

If the gear is stuck, you can gently pry the gear up to loosen it, or just tap on it gently then try starting again. If that works, then try cleaning the shaft where the gear rides with some carb. cleaner, then a little lubrication. Some WD-40 or better yet, some dry molly or graphite.

 

[Jiggz]

If you actually follow the lube chart for these motors, you are required to lube the flywheel gear teeth and also the bendix gear teeth with light or bearing grease. The starter shaft should also be lightly oiled or a very thin grease. I'm not really sure what happened to the old starter or the previous 2 starters, but this is the first time I heard someone changing starter 3 times in 3 months!

 

[New.boater]

Thank you Captain and Commander for your input. I appreciate all your ideas.
I can't do much about the solenoid or bad starter, because that is beyond my skills. As to the WD40, I did put some into the top part of the starter shaft where the spring is and into the cylinder but without success when I tried to start the motor. All it does is spin and turn but does not engage the fly wheel.

 

[Jiggz]

Can you post a picture of the starter bendix while installed showing the relation of the bendix gear, starter shaft and the flywheel? Anyways, first you need to make sure the bendix unit is not stuck in the starter shaft. This can easily happen since after the engine starts, the pinion gear gets overrun by the flywheel due to high gear ratio, meaning instead of the pinion gear driving the flywheel, when engine starts, the flywheel will drive the pinion gear or bendix. As such, the bendix gear will screw back down to the starter shaft, and this can be a hard reset or not depending how long you held the switch in on position making the starter to continue turning and gaining speed (it is a series motor hence will continue to gain rpm if held for too long) and pushing back the bendix against the flywheel. But this time since the flywheel is already turning, it will not allow the pinion gear to engage thus you hear a metallic grinding noise.

So using a screwdriver, make sure the bendix gear is freely turning (and it should screw up to the starter shaft while you manually turn it) and riding up and down the shaft. While the gear is up, apply some light grease or oil where the bendix gear sits when idle. Then try again and let us know what happens. As I have mentioned apply some light bearing grease to the flywheel and pinion gear teeth. You can even do a simple test by spinning the bendix gear clockwise (looking form the top) hard like simulating a overrun and see if it gets stuck at the bottom of the shaft. If it does, you need to clear what causes it to get stuck for it is not supposed to be.

Note: Others vehemently object to greasing or oiling the starter shaft for the reason that it accumulates dirt or becoming a dirt magnet. This could be true but only if you decide to padlock the cowl and never to do any maintenance on the starter pinion after greasing it. The fact is, the starter pinion needs to be lubed every 30 days or more often especially if used in seawater.

 

[New.boater]

Here are the pix.

 

[Jiggz]

Unfortunately, I cannot click on the pics. All I can see are icons but not links.

 

[New.boater]

Let me try again..... to load the pix.

 

[New.boater]

Let me try again..... to load the pix.

 

[New.boater]

Let me try again..... to load the pix.

 

[New.boater]

2 more pix.

 

[New.boater]

As you can see the teeth from the starter are lower than the teeth from the flywheel. What would cause the starter teeth to jump up and engage the teeth of the
flywheel and start the motor? Or crank the motor?

 

[Jiggz]

The pinion gear or bendix unit (this is the correct term if referring to the clutch and gear unit otherwise you can just call it the pinion gear - which is the gear part that engages the flywheel gear. There are screw splines on the starter shaft where the bendix unit seats at rest. When the starter motor turns, the bendix unit because of its weight (potential energy) will initially try to resist turning with the starter shaft, as a result it will "screw" up the splines moving up. With the upward force and turning force, it will engage the flywheel gear or teeth and thereafter will turn the crankshaft to start the motor.

However, if the bendix unit is stuck at the bottom of the starter shaft or has some binding that prevents it from sliding up, it will instead just turn with the shaft without sliding up. If it fails to slide up for the first micro second that the starter shaft starts turning, then it will continue to turn at the same high speed as the starter and will never be able to engage the flywheel gear. This is the metal grinding sound you get when the starter pinion gear doesn't engage.

The requirement is that the bendix unit should be free to slide up the starter shaft, that with initial turning of the starter, it will screw up the splines to engage the flywheel before the starter increases in rpm. And most of the time all it takes is lubricating the shaft and the splines under the bendix unit.