bendix gear slipping - Presto lite starter

[bjhc100]

Force 125 HP 1986. There must be a clutch internal to the bendix drive? If so mine is slipping and the small hub that contains the disks part is heating up. The rest of the starter is not heating up, nor are the cables or connections. It just started last time out. How common is this, I guess a new bendix gear is in order, does it make more sense to order a new starter complete with bendix. Its on a '86 125 HP. What does it mean? Could something else be wrong? Any help is good. HC

 

[pnwboat]

Re: bendix gear slipping - Presto lite starter

That's a strange symptom. The bendex does not contain any disks like a transmission clutch. Does the engine start OK? What symptoms are you experiencing?

 

[Frank Acampora]

Re: bendix gear slipping - Presto lite starter

Sorry, PNWBOAT: There is friction material in the lower collar of the bendix. Occasionally it wears and the collar will slip when the bendix engages the pinion with the flywheel.

bjhc: That starter simply needs another bendix assembly. As far as I know, it is not easily repairable. You can try re-crimping the collar to tighten the friction material but I don't think you will have much luck.

Try a starter repair shop before you go to spring for the big bucks for a new starter. It will be a lot cheaper to buy a new bendix from them.

You will need to de-mount the starter to remove the bendix AND the top nut is deformed thread self locking and very tight so it will be a bit difficult to remove.

 

[bjhc100]

Re: bendix gear slipping - Presto lite starter

Hey Frank, Thanks for the feedback. A new brush kit was installed last year so that end of the starter seems ok. It does crank the engine over when the bendix gear does not slip. I will take the starter to local guy who does this type of work, he is familiar with this starter. He could maybe use the business about now. Question, should the top nut that retains the bendix gear be replaced with a new one, or is it ok to re-use the old one. And is there a standard RPM for cranking the engine, like a minimum recommended cranking speed? Assume good wiring, connections, and battery. Harley

 

[jerryjerry05]

Re: bendix gear slipping - Presto lite starter

I have a rebuilt starter for sale.I have twin 88/85hp and found it best to have
a spare.They always seem to go out at the worst time.That bendix can be had at any starter shop.
I'm replacing my twins with a single Merc and will have a lot of stuff for sale. Jerry

 

[Frank Acampora]

Re: bendix gear slipping - Presto lite starter

Well, first I need to correct myself. The internals of the lower collar on the bendix is probably a one-way clutch. It would function to prevent the starter motor from overspeed when the engine fires and before the bendix disengages. It would probably also be a safety in case the operatot keeps the starter engaged after the engine starts.

It would PROBABLY consist of two rollers on a cam. when the starter turns, the cam forces the rollers out to the perimeter where they lock-up like a clutch. When the engine spins the bendix the opposite direction, the rollers disengage. Now, of course, if the rollers do not engage but skid along the perimeter, a lot of heat will be generated.

The top nut can be re-used, I have done so numerous times with no ill effects but be certain you get it on tight again.

Since the stator acts like a magneto, if the starter turns the engine too slowly, the CD charge coils in the stator will not generate a high enough voltage for positive starts. For this and other reasons, normal cranking speed is between 350-550 RPM.

 

[bjhc100]

Re: bendix gear slipping - Presto lite starter

Ok, Thats good info and a friction roller set up makes perfect sense. Cause once it is worn and begins to slip it makes a high pitch squeal and really gets hot fast, like metal on metal.I think the parts then expand and then grab due to thermal growth. The cranking speed is a lot higher than I figured, considering these old Forces motors can, as least in theory, be manually started with a pull rope. Course, I have not ever tried to calculate how fast I could spin it over with a rope either, crazy stuff 'eh. Maybe the tack will tell, I never paid any attention to it when starting. Oh, is the top nut a standard right hand thread? Harley