Rotostart won't turn engine when plug is in

[Firestat]

Forgive me if this has been posted before, but I am new to the forum and can't find an answer.

I have an original Savage 21, with the 25 engine in it, about 9 years old.
Up until this morning, it was starting just fine, then all of a sudden, the rotostart just spun and spun, not kicking the engine over. I took the plug out, and I could see the piston going up and down when I used the rotostart.
I put the plug back in, and no go, just spun and spun.

Any help would be appreciated.

Thanks.

 

[JohnH]

sounds like the one way bearing is messed up. it will spin with no load on the motor but as soon as you have a load on it it slips. don't know your motor but if it has an internal owb you may want to pull it and check it (also clean it) you could send metal into the motor.

 

[Firestat]

Thanks, I sort of thought that might be the case (trying to remember from the old days since I just started playing with it again). I will check it out.

 

[k0m0d067]

sounds like the one way bearing is messed up. it will spin with no load on the motor but as soon as you have a load on it it slips. don't know your motor but if it has an internal owb you may want to pull it and check it (also clean it) you could send metal into the motor.

well, I'm guessing he's running the HPI NS .25..if that's the case, it's axternal...just under the rotostart backplate...

 

[Firestat]

Ko, that is exactly correct. I pulled the engine and the back plate. Question is, is it the bearing over the shaft that I need to replace, or the gears in the housing. I really couldn't see anything wrong with the bearing meaning I could not turn by hand, but as soon as I put everything back together again, and applied the rotostart, it just spun and spun without kicking over the engine. Guess I need to replace?

 

[JohnH]

try to clean it in alcohol and see if it locks up or just buy a new one. they build up sludge and the flats on the needles don't hit or it can get hot and melt the plastic race holding the needles.

 

[oregonmud]

I also like to replace the shaft that the OWB fits onto. It will make the new bearing last a lot longer.

 

[Firestat]

Ok, guys, back in action. Thanks, again for all your help.