Possible stator issue

paw2000

Petty Officer 2nd Class
Joined
Jul 9, 2009
Messages
106
Hi, been searching for some ideas. Here is the situation, fresh plugs, gas, run motor sounds good. ran in tub and also on ear muffs. Take boat out, start it up and it idles ok then shuts off (like a backfire)restart at fast idle warms up, take off. Give it throttle the boat speeds up, then accelerate to full throttle, and the boat is just pushing water. I stop to verify throttle is full open and it is. I'm not smelling unburned fuel and at quarter throttle motor runs fine.

So thinking its fuel, check filters, carbs, then I go thru the ignition and check stator. I got about 510vac on 1 and 2 leads 3 and 4 about 150vac. So it looks like a bad stator. Tho this motor is firing the spark plugs at low speed. Is this how stators behave when they fail, idle speeds are fine, anything faster spark goes away? The motor is an 1988 125 force
 

pnwboat

Rear Admiral
Joined
Oct 8, 2007
Messages
4,251
Re: Possible stator issue

You can verify that it's the stator by measuring the stator windings. Disconnect one of the leads when measuring resistance. You should read 680-850 Ohms between each pair of the yellow and blue stator leads. Make sure the leads are not rubbing against the flywheel and shorting to the block too.
 

paw2000

Petty Officer 2nd Class
Joined
Jul 9, 2009
Messages
106
Re: Possible stator issue

I measured the windings got 719 ohms on 1 pair and about 715 on the other, the leads to rectifer is about 1.1 ohm. So it measures good? I pulled the flywheel off (wasn't easy) and the internal magnet was loose and made pulling the flywheel difficult. Can the magnet be the cause?

If you or others have any other specs to check with a meter, I'll try anything. If the magnet would "slip" would this effect the timing? like if the poles of the stator didn't line up with the magnet and not get voltage?

Paul
 

paw2000

Petty Officer 2nd Class
Joined
Jul 9, 2009
Messages
106
Re: Possible stator issue

I read some other posts about the magnets and how they are loose. So when I got the low voltage on leads 3 and 4 this was actual inducted voltage from the stator? I used a digital meter set for Volts ac, is this ok to do? I don't have access to a DVA the manual states.

I'm thinking if the magnets (band) has slipped it would or could it? induce a higher voltage on 1 set and a lower voltage on the other because they are not "phased" not sure if these are correct terms. I got 510vac on 1 2 and 3 4 was 150vac. the manual says it bad but the resistance is nearly identical.

Any thoughts?
paul
 
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