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Discussion Starter · #1 ·
ok...this puzzles me...I was give a really good looking mower with a briggs twin cylinder 18.5 hp engine...the starter gear was cracked in half..so i bought a starter gear...put it on..and the teeth were striped in just a few starts...so I examined the flywheel and saw a tooth missing...so I thought that must be the problem....so I replaced the flywheel with one that I had....same number of teeth...same size....and put another plastic starter gear on.....and once again in about 6 starts the teeth are missing!!...

I read on the internet for hours...and some of the things that might cause this are.....the compression release??..does this model even have a compression release??..

1 loose bearing in the starter...but it seems tight to me...
2 worn flywheel.....all the teeth are there and no signs of wear...
3 compression release not working...does it have one?..how does one check it?
4???

any help would be great..this is frustrating..this starter is tough to take out and put back...thanks
 

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Deere 330 Killer
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does your starter gear go in and out as it should?
 

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Discussion Starter · #3 ·
Hey Hugh..thanks for the reply....well..yes I think so..because it would move the flywheel and actually worked very well for the first three starts or so...then a little grinding noise..then A LOT OF GRINDING!!...then all the teeth were gone!!...I changed briggs starters before that were not so difficult to remove and replace...but this starter is tough...so its frustrating!
 

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Discussion Starter · #4 ·
I have just read on another post that some riggs engines use a metal gear for the starter??..depending on flywheel??..could that be an issue?..the engine model calls for a plastic gear I think..I know the flywheel I put on is metal...but the one I replaced was metal too...unless somone changed it out to the wrong one before I owned the mower..well..just an idea??
 

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Deere 330 Killer
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i wonder if your starter gear wasnt popping in after the engine starts. if it stays out while the engine runs, that may be the cause of the noise
 

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Could be a compression issue, too much compression to allow the starter to turn the engine? Just guessing here.
 

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Discussion Starter · #7 ·
what would prevent the starter gear from popping out?...weak spring?...I dont know about the compression being too much...I mean how would I check that??
 

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Deere 330 Killer
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no the problem is the starter gear is STAYING out. it is supposed to pop out to start the engine, then pop in while it runs. maybe your spring is too strong for the new gear or the new gear is longer and sticks out
 

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It is always helpful if you post the model number of the engine in question. B&S 18.5 twin does not really identify it.

Flywheels with aluminum ring gears should use a nylon starter gear. Aftermarket starter gears often do not hold up on larger B&S engines. I always use B&S brand starter gears for this reason. IF the flywheel ring gear is steel, it should use a metallic starter gear.

Are you putting the starter gear on right side up? You may have a worn out starter clutch ***'y, the spiral maybe worn until the gear is not being help straight. You may want to check that the starter gear comes up far enough to fully engage the ring gear. I saw one the other day that only came up half way, wrong replacement ring gear on flywheel.

Bushings in the starter will NOT wear to the point of causing this problem because the starter armature will drag on the starter fields first. Too strong a starter spring?? That is to dis-engage the gear, not engage it and isn't even really needed.

Walt Conner
 

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Discussion Starter · #10 ·
thanks Walt for the info...the model is 42a707 ...type 1238 01...code 9506015a...maybe they sold me the wrong starter gear....the ring gear is aluminum...maybe they sold me the plastic one...the gear engages the flywheel maybe 3/4 of the way...is that normal?..the bottom 1/4 is not chewed up and apparently was not engaged..the gear will tilt on the spiral shaft until it reaches the top...is that normal?...thanks again...really hoping to get this thing going!..
 

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Not sure what you mean by the starter gear will "tilt" on the spiral shaft until it reaches the top? Perhaps you could manually advance the gear and post a picture of what you're seeing!? Sometimes...a picture is worth a thousand words...Gosh, now where have I heard that before??:confused:

thanks Walt for the info...the model is 42a707 ...type 1238 01...code 9506015a...maybe they sold me the wrong starter gear....the ring gear is aluminum...maybe they sold me the plastic one...the gear engages the flywheel maybe 3/4 of the way...is that normal?..the bottom 1/4 is not chewed up and apparently was not engaged..the gear will tilt on the spiral shaft until it reaches the top...is that normal?...thanks again...really hoping to get this thing going!..
 

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As said before, the starter is supposed to pop up and engage the flywheel and then centrifugal force causes it to disengage. There are several reasons why this might not happen. the shaft the gear rides on may be dirty and it can not return own its own.
the gear may be the wrong one, and if it is a bit over size, it might not be able to disengage. Sometimes you might have to put a small shim between the starter mounting holes and the block to keep it from becoming stuck in the engaged position. Try using the thinnest washer you can find, or an old feeler gage of a few thousands in thickness. The best thing to do is first as suggested earlier, remove the cowling on the engine and then engage the starter. That way you can see first hand what is going on.
 

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Discussion Starter · #14 ·
ok guys...just got your last messages...I will remove the cowling and try that...the gear will definately go to the top of the spiral shaft..but I do not know if it is returning properly...and the starter gear does tilt on the spiral shaft if you push on it with your finger...until it reaches the metal ring at the top then it no longer tilts...I will try removing the cover...and let you know what I see
 

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"Sometimes you might have to put a small shim between the starter mounting holes and the block to keep it from becoming stuck in the engaged position."

I had this same thought. Perhaps a spacer washer has been lost by the PO when working on the starter?? Causing the starter gear to mesh too tight in the flywheel gear???
 

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""Sometimes you might have to put a small shim between the starter mounting holes and the block to keep it from becoming stuck in the engaged position.""

In about 60 years of working on small engines I have never heard of nor encountered this. IF it is a B&S brand starter gear, it will be the right size. IF a shin is needed, there is a problem with the starter drive ***'y.

Walt Conner
 
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