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dferg_gw

ring gear is the problem not the starter?

dferg
12 years ago

I have a B&S Model 28Q777 Type: 0681-01 engine on a Scotts riding mower. Last year the starter gear broke. I replaced the entire starter with a NON B&S starter. It worked for approximately 10 starts until the gear broke again. I returned it for another whole new starter and it broke again after two starts. Then I replaced just the starter gear and it worked for about 6 starts till the gear flew up into the ring gear jammed and broke the retaining cap that sits on top of the bendix gear (although the bendix survived intact). I can see no discernible problem with the ring gear under the flywheel. It is quite old so there may be some tooth thinning that is too uniform to see. There are no teeth missing or damaged. My question is, should I replace the after market starter again or go to the trouble of replacing both the starter and the ring gear? It is the engine with the aluminum ring gear and requires the plastic bendix gear. Thanks so much for your help.

Comments (26)

  • walt2002
    12 years ago

    There generally is not a problem with the aluminum ring gears. I don't know why on earth you would replace an entire starter for a bad pinion gear.

    ARE you using B&S Pinion gear? IF not, that is probably your problem.

    Walt Conner

  • tomplum
    12 years ago

    My experience too is that the aftermarket pinion gears are ill fitting and break. Are you also having a problem to where the engine seems difficult to crank?

  • dferg
    Original Author
    12 years ago

    Yes it is a Briggs & Stratton bendix which did not break this last event. I watched the gear fly up and the top washer broke in half and the bendix remained intact. However the starter is not a B&S one. Ideas on the next step is appreciated.

  • walt2002
    12 years ago

    In over 65 years of working on small engines, I have not encounter anything as you describe. I think you are missing, leaving out, something.

    Walt Conner

  • walt2002
    12 years ago

    As a follow up, a few days ago, on one of the Forums I monitor, a person had an aftermarket starter on which the mounting bracket was not the same length, distance from starter to engine, as the original damaging the pinion gear and not engaging properly.

    Walt Conner

  • tomplum
    12 years ago

    Maybe the aftermarket starter spec is not close enough. It may be more likely that the wrong gear has been installed. Though Briggs offers different length starters, and specific starters for steel vs aluminum ring gears- the difference is in the pinion gear itself. It is cut different at the top. The bendix complete is #696541 for the aluminum ring gear. Briggs does make an aluminum service ring gear, but specifies that it is to replace the plastic ring gear.

  • walt2002
    12 years ago

    " I watched the gear fly up and the top washer broke in half and the bendix remained intact. However the starter is not a B&S one."

    From a remark made, I wonder if the gear is coming up too far hitting the flywheel its' self above the ring gear breaking the gear.

    As an additional comment, in the years I mentioned working on small engines, I have never bought a new B&S starter, always being able to either repair the original or having a good used replacement.

    Walt Conner

  • dferg
    Original Author
    12 years ago

    As far as acquiring a new starter, I was told at the time by my local Napa auto that the bendix was not replaceable and I had to buy a whole new one. I have since found out differently on-line. It is gone now and I must deal with the present situation. Can you recommend the appropriate B&S starter and I will try again. AS I stated previously I watched the retaining washer break in half as I started the engine. Thanks

  • walt2002
    12 years ago

    I would have used the original starter and installed a new genuine B&S pinion gear.

    Walt Conner

  • tomplum
    12 years ago

    For the aluminum ring gear, 499521 is the starter is the long version (4 3/8" housing) 693054 is the shorter (3 5/8"). If in doubt, use the shorty. If the gear is coming up too far, maybe you could slightly elongate the holes to allow for a lower mounting.

  • walt2002
    12 years ago

    Hmm, body length has nothing to do with mounting location. The mounting bracket is the same. I often switch, use interchangeably.

    Walt Conner

  • dferg
    Original Author
    12 years ago

    Okay, Thanks for the advice. I have the parts diagram and see the numbers you are referring to. Since I no longer have the original starter I will try and measure somehow accurately the distance between the starter mounting holes and the top of the ring gear. I cannot envision what exactly that will help me with when deciding between the shorter or longer version. I have seen in other posts that some bendix were only engaging about half of the gear and this person modified the mount to engage the entire ring gear surface. Should this be the case or is say, 70 percent of the way enough? Thanks for your time.

  • dbkh
    12 years ago

    I've found that there is less wear on the pinion gear if I leave off that spring. Once the engine fires it kicks it back down anyway. The spring, from what I've seen, just causes more wear on the pinion gear.
    Could try it without the spring.

  • walt2002
    12 years ago

    Has it occurred to you that you would have been money ahead to have taken it to a pro in the beginning?

    Walt Conner

  • dferg
    Original Author
    12 years ago

    Gee Walt you must be really disgusted with my post, since several of your your comments are quite critical and judgmental. I live in the middle of no where and would have to have the mower hauled, I am still way ahead money wise just because of that. I haven't visited a forum before but I guess there are always people who are in it for their ego's more than anything else.

    Everyone else Thanks so much!

  • tomplum
    12 years ago

    Can you post a pic of the wear?

  • walt2002
    12 years ago

    "Gee Walt you must be really disgusted with my post, since several of your your comments are quite critical and judgmental." "I haven't visited a forum before but I guess there are always people who are in it for their ego's more than anything else.
    Everyone else Thanks so much!"

    Well I guess you really got me told off. Feel better? Several posts?? I have a surplus of complete B&S Starters but they are not available now and won't clutter the thread further.

    Tomplum, I have a puzzle on that if you want to email me.

    Walt Conner
    wconner5 at frontier dot com

  • Stevep801
    12 years ago

    Walt, I just removed the flywheel off of my 15.5hp Craftsman riding mower to replace the sheared off teeth on Ring Gear and noticed the ring gear is attached with pins. How do you remove the pins?

  • tomplum
    12 years ago

    Personally, I use an abrasive cutting wheel cut right through the nylon ring gear and through the pins. Then drive them out with a punch.

  • Stevep801
    12 years ago

    Thank you Walt. U da Man!

  • Stevep801
    12 years ago

    Walt, I'm kind of in a pinch here and not sure what to do next. I bought a used Craftsman 15.5hp riding lawnmower and I've tried everything in my box of tricks to get it to run but the best I can get out of it is a pop once and that is it. I'm getting great spark and the motor turns over perfectly although the compressions is a bit tight. I've removed the plug and forced gas into the piston hoping this would do the trick....nothing. removed the ground wire from the coil to make sure there wasn't a ground out somewhere...no help. I'm jumping the starter as the ignition doesn't want to work. is there a way to bypass all the safety switches? figure if I'm getting good spark the switches shouldn't be the problem. Oh well, please respond if you have any ideas. Thanks in advance for your help as I really appreciate it.

  • tomplum
    12 years ago

    You've got too many variables here. You have spark with everything hooked up? It may be that the flywheel wasn't secured enough and you spun the flywheel key. For most of these to crank, set the park brake and turn the key w/ the pto disengaged. 1 small terminal on the solenoid will need a ground when the safety line is correct and one 12v when the key is hit. You state that the compression seems "tight". Excessive valve lash will prevent the compression release from functioning as it should. A quick search will tell you what you need to know. The model # from below the seat would be helpful along with more specifics.

  • Stevep801
    12 years ago

    Thanks for your reply Walt. I have excellent spark when the motor cranks. I pulled the FW fan and viewed the flywheel to make sure the key is lined up and it is. It was one of those deals where the seller communicated that the motor worked fine but I'm starting to have my doubts. I viewed a video on youtube where the guy had the same problem. turned out the valve rod was bent and the piston was shot. I've got a spare engine that works but was hoping I wouldn't have to exchange. Thanks again for your timely response.

  • mownie
    12 years ago

    We sure have a lot of "Walts" on this forum :^)

  • tomplum
    12 years ago

    Heh heh...
    I'm thinking that the new poster could possibly channel the real Walt via a new thread- as Walt had washed his hands of this one. Me, I just play one on tv....

  • Stevep801
    12 years ago

    whoops...lol....sorry Tom. I'm a newbie here. Thx for ur help.

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