OutdoorKing Repair Forum Forums Restoring, Customising and Modifying Tech Talk Briggs and Stratton 2 stroke

Hi All, I've followed this forum for about a year now and i find it priceless what info can be found here. I've eventually stumbled across a mower that's got me beat so here i am hopefully tapping into the wealth of experience that lies therein.
Its a masport contractor with a 2 stroke briggs model:95722, type:0220-01, code:891006.
So here's the problem. Initially not starting mainly due to the fact that the choke was not engaging at full throttle, and it had one hell of a kickback also, although i got it started after spraying a small amount of starter fluid in the plug hole. The motor ran fine and restarts were not a problem after the motor was warm.
After adjusting the throttle cable i could not get it to restart, it fired on a few occassions but would not actually start, all the while that super intense kickback was ripping the starter cord out of my hand.
Now i'm guessing it might be a flywheel key causing the timing to be out. i will strip it down tomorrow to have a look but thought i'd get some ideas here first

Hi Rice, welcome to Outdoorking.

There are two likely causes of starter-kickback with that engine. By far the more common one, is that you do not have sufficient rotational inertia attached to the crankshaft. Normally this happens because someone is trying to start the engine without a proper blade or blade plate installed on the crankshaft, or it is installed loosely so it is not rigidly a part of the crankshaft. The other, less common cause is that a sheared flywheel key has resulted in the flywheel being stuck in a position a few degrees clockwise from where it would be if the key were not sheared.

Hi Rice,

Do those mowers have belleville washers like Victa 2 strokes? I know I've put them on upside down and then get kickback while trying to start them.

I've added quite a few pictures from different angles for members to peruse. As can be seen in the 4th pic, yes, the flywheel key was sheared and was out about 20 degrees. Its a half moon shaped key which measures up the same size as an earlier rover blade boss key. Now i have to find a new starter pulley as the old one cracked around the pawls because of the kickback (any ideas where to source a new one locally would be helpful)

Briggs flywheel keys are usually made out of zinc so they can be sheared when the blade impacts something with enough force so that if the key did not shear, the crankshaft would break. If you have to make your own Woodruff key replacement, zinc will be hard to come by and you may have to make it out of aluminium. Do not use a steel key, such as the blade boss key, or the next time you hit something your crankshaft will fail in torsion. I think you have little chance of buying parts for that engine, but to find out for sure you should send a PM to Bruce, the Outdoorking site-owner: he will know for sure.

Here is the last Woodruff key I had to make - must be nearly a year ago now:


It is fairly straightforward filing.

Not tryin to go off subject but how hard are these engines to come by? Cause my father inlaw has a masport with one of these engines? N i didn think briggs made 2 strokes lol

Nathan, Briggs did not make 2 strokes. They struck a deal with Komatsu Zenoah to do that for them. Then it turned out to be financially unviable so they stopped after a couple of years.

I do not think the engines are rare, but if you wanted one you'd have to expect to go looking for it rather than pick one up from a nearby tip-shop. I have the impression it is quite a good engine, comparable with a Suzuki or Kawasaki.

Ok thanks for that. An so spare/replacment parts wouldn be to easy to get?

I don't know, Nathan, there is a good chance someone has them, in Japan or the US if not here. Bruce is the best place to start.

Can you post a photo of the broken starter part and I will compare them to other motors around the yard here, from there I could point you in the right direction for that part.

I reckon a masport craftman top/starter looks exact same almost i got one in the shed

Thanks Joe, here are some pics of the starter, This unit only runs 1 dog as is evident by the 1 notch in the retainer. The retainer also has a hairline crack because it bent all the way around when it let go(as per pics). I bent it back around but it will inevitably snap off. The pulley has snapped both the mounts(they obviously have 2 so when one lets go you can use the other). The good news is these parts are available locally, the bad news is they come at a premium. Pulley $36, retainer $30. The key is affordable at $4. i would definately be interesed in a decent 2nd hand starter though. If you have anything thats remotely close let me know and we'll go from there. Nathan, i'd be interested to see a photo of the one you have.
The starter itself stands a lot taller than most "quantum" style starters and the starter cup is also considerably taller, althogh the mounting holes are equally spaced. A worst case scenario might be to modify the cup and starter off a quantum.

Gents, thanks for your input and advice. I managed to source a used starter at my local mower shop (that was lucky) for a about half of what it would have cost me for the parts i would've needed to repair it. As for the flywheel key, yes, i replaced it with a zinc one. After that, the mower starts first/second pull every time; quite a smooth and very torqy unit.