Broken Crankshaft?

[wildcard]

hey, I'm new with these lil things, i have some experience with bigger motors but i wuz runnin my 4.6 one day and i flipped it then i died for sum reason and the the starter didnt catch anyting when i went to start it again, it just spun. so i took it apart and the OWB worked jst fine but i noticed that the shaft the OWB slips onto moves in and out like a 1/16 of an in. when i push it in it catches and the the motor will turn over when its out to doesn't catch anything, is that a broken crankshaft or what is it?? fixable??..

 

[olds97_lss]

Sounds like you've worn out most of the good of the OWB and starter shaft. If you've had the OWB for quite a few gallons, it's a good idea to replace both the starter shaft and OWB at the same time. An old shaft that's worn won't work real long with a new bearing and will actually shorten the new bearings life.

I don't know your engine specifically, but most of them have a soft spring that goes between the end of that shaft and the starter housing to help keep the shaft pushed into the engine all the way. If yours only takes that much to make it bite, then I'd still say the parts are worn and should be replaced.

 

[wildcard]

icic, how hard would it be to replace the starter shaft?? there wasn't a spring in there but ill get a new OWB and starter shaft and see wat happens, thnx

 

[olds97_lss]

What engine is it specifically? Usually not real hard though. You may want to take the starter housing off and the backplate off to make sure you don't have a more serious issue, like the starter pin on the crank being worn off.

If it's the K4.6, the pin appears to be part of the OWB itself and goes into a hole on the crank. I've never had an engine like that. All the ones I had had a nub/pin on the crank itself that went into a slot on the OWB.

Starter shaft (for the K4.6):
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXJYU7&P=Z

OWB:
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXJYU6&P=Z

 

[wildcard]

i have the F4.6 not the K4.6, is there much of a difference??

 

[olds97_lss]

Yes, completely different design. The F4.6 uses an external OWB. Still, it has a pin inside the center of the crankshaft that is spring loaded. Now I'm wondering if that's just gummed up inside your engine and the pin isn't extending like it should to press into the slot of the starter shaft disk.

OWB:
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXDLN7&P=Z

Starter shaft:
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXFRD3&P=Z

Starter shaft pin that goes into the end of the crank:
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXDLN9&P=Z

Sounds like it's time for a tear down.

Pull start or roto start?

 

[wildcard]

roto start, i took the back plate off and it look like my starter shaft is wore quite a bit... also does that spring go in behind the starter pin??

 

[olds97_lss]

Yes, it goes into the crank shaft itself and hold the pin against the big disk on the back side of the starter shaft.

 

[wildcard]

icic.. i looked at the starter shaft again nd its prolly fine but i dont think the spring is pushing the pin out far enough to catch on that disk nd that mite be my problem

 

[wildcard]

finally got the spring out.. all 3 pieces of it, definetly the prob, thnx for the help!

 

[nate r]

yea mine is doing the same thing, just sits there spinning wont go into gear.