Pullstart Not Cranking over engine.
 

Hi, I have a Force Models 3.5 Engine. The engine is very new, maybe 3-4 tanks of fuel used. It is on an Art Attack snowmobile. Iwent to pullstart it, and it just pulls freely, doesn't crank over the engine. I know theone way bearing is working correctly becuase Itook the pullstart apart and I can see it spinning the axle that its on.(It's grabbing very good) Ihave taken some photos. They can be viewed here:

http://www.flickr.com/photos/2761257...7626041524266/

Ihave no idea how this thing is suppose to work. It almost looks like there should be a pin sticking out that the round piece would grab onto to crank the piston... Anyone have any ideas of what is wrong here?


Thanks!

RE: Pullstart Not Cranking over engine.
 

Looks like someone has swapped a pull start of different style over to your engine?

RE: Pullstart Not Cranking over engine.
 

With this type of pull start, there is a spring loaded pin that projects from the center of the hollow crank pin.
From the pic it looks like either the pin is pushed all the way in and stuck there...maybe the spring has stuck or it's missing....OR the pin has sheared off flush.

I have several of these, and worked on many others...it might be as simple as un-sticking a gummy spring. Or you might need to get another spring, if yours got lost...they can go "poing";) and fly out for several feet, and get lost quite easily...(voice of experience here :eek::D )

Use some fuel on the crank pin to try and dissolve any sticky residue, and work on the pin, wiggle and jiggle it to loosen it...then try and remove it w/ a magnet or forceps, needle nose pliers, etc.
Watch for that little spring!

RE: Pullstart Not Cranking over engine.
 

It looks like someone took a pull start unit and tried to use it on a non-pull start engine. The crankpin on the crankshaft (where the connecting rod slips onto) needs to be longer so that it engages the slot in the pull start disc. So thus it won't work like shown in the pics.
Anyway, you'll need a different crankshaft for that, if they make one for that engine. othewrwise you have to use a car electric starter stand to fire up the engine. Now if the flywheel has a decent groove, you may be able to use a cord to start it off the flywheel, that was the old fashioned method many years ago, before they came up with electric starters or pull starters for the engines.

RE: Pullstart Not Cranking over engine.
 

From the middle picture, it looks like the outer part of the crankpin is broke off. Its hard to tell from the pictures for sure, but it looks like the starter pin is broke off.

Did you break the engine in or have you ran it prior to this or did you get the engine in the present condition and haven't ran it yet?

RE: Pullstart Not Cranking over engine.
 

Ithink proptop might be correct it could be stuck in. Yes I did break-in the engine. It's been in storage for several years, so makes sense now that it could be stuck in. Ijust looked at it, and it doesn't appear to be cracked off, it is too smooth looking.If it did crack off, wouldn't their be some severe damage done to the inside of the engine Piston, cylinderetc? Iput some fuel on inside and closed it up, hopefully the pin will come back out, if its stuck in. Tomorrow I will get out my camera with a macro lens and take a nice closeup of that crankpin.


Thanks to all the other posters...

RE: Pullstart Not Cranking over engine.
 

Yep...after looking at the pics again, there's a pretty good chance that the pin is just stuck.

On those "Force" engines, the crankpin is open, or a blind hole, with a very small spring in there, and a small hardened steel pin resides in that hole.

The backplate's starter disc has a semicircular slot or groove machined in it (easily visable in the photo ) but what's not easy to see, is that the groove is ramped, to provide a cam like action.
As the backplate rotates (by the pulling of the starter cord ) it engages the spring loaded pin.

It's not the best set-up, but it works...

I do some part time "Mr. Fixit" work for a LHS and (besides having a couple of OFNA LD3's of my own, w/ Force .12's ) have seen this happen a few times.

RE: Pullstart Not Cranking over engine.
 

Ok I looked at the pics again. Stupid me, my apologies, yes it looks like the pin is stuck inside the crankpin.
You can heat it up with a hot air gun and that should loosen it up so you can clean and oil the pin and spring.
Be careful as it might shoot off across the room never to be seen again.

RE: Pullstart Not Cranking over engine.
 

SUCCESS!!Ijust opened it back up after soaking for 2 days.Noticed the pin was missing!The pin came out and was laying on top of the bearing. http://www.rcuniverse.com/forum/js/f...eeth_smile.gif Pullstart works like a champ once again!


http://www.flickr.com/photos/2761257...n/photostream/


Thanks a lot for the replies. Thumbs up to Proptop!

RE: Pullstart Not Cranking over engine.
 

A-Ha!
Cool...:D