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I have a 1978 Lawn Boy 5275. Runs great.


I have a problem. The pull start cog can't engage with the flywheel teeth because the flywheel is too low or the pull start cog is too high. The starter moves over appropriately when pulled and moves back when release. The ()#@*$@)(*$@ starter cog just doesn't have the clearance to engage.

Here is a picture of what is happening.



Can someone help me fix this?

First post to this forum.


Thanks,

More than likely the crank has been bearing down on the crankcase. Check the crank play is excessive, not side to side, but up and down. If excessive then I would replace the crankcase. The crank should be good since it's cast iron, all the wear will take place on the bottom, inside surface of the crankcase.
EDIT: Shims or thrust washers would be another option, but putting a good crankcase in the mix would be best. Some previous owner probably ran without air filter in place and got grit in there causing premature wear.

Lawnboy77 said:

More than likely the crank has been bearing down on the crankcase. Check the crank play is excessive, not side to side, but up and down. If excessive then I would replace the crankcase. The crank should be good since it's cast iron, all the wear will take place on the bottom, inside surface of the crankcase.
EDIT: Shims or thrust washers would be another option, but putting a good crankcase in the mix would be best. Some previous owner probably ran without air filter in place and got grit in there causing premature wear.

Click to expand...

I'm interested in the shim route. What kind of shim does one use?

something like this. The later F series engines addressed this issue and included these thrust bearings and washer to prevent what you are going through. Measure your play for me, I may have something I can set you up with.

Lawnboy77 said:

something like this. The later F series engines addressed this issue and included these thrust bearings and washer to prevent what you are going through. Measure your play for me, I may have something I can set you up with.

Click to expand...

Thanks for the pic and the offer. I assume I'll have to tear the motor apart to get that measurement fore you? It may be awhile before I have time to do that.

No problem, glad to be able to help. Ah don't worry about sending any measurements, I'll just send you what I have, which is what you see in the pic and you can add or take away to get a good end play. Just pm me with your address and I'll send it out to you ASAP.

The part numbers for the washer and bearing are:

Thrust bearing 252-76
Washer 252-80

You can Look up these parts by punching in the latest version of just about any F series produced after 1996. To get those numbers I looked it up by way of a 1996 model 10401.

Have you tried adjusting it? The manual doesn't really talk about using shims, but they do mention a certain amount of clearance. The recoil shaft is splined and needs to be set just so, basically. They are pretty simple arrangement. If you choose to remove it, follow the manual instructions. A third hand is helpful for this procedure.

The LawnBoy manual for these mowers and many others is available for free download, maintained very helpfully by Toro.

Teds said:

Have you tried adjusting it? The manual doesn't really talk about using shims, but they do mention a certain amount of clearance. The recoil shaft is splined and needs to be set just so, basically. They are pretty simple arrangement. If you choose to remove it, follow the manual instructions. A third hand is helpful for this procedure.

The LawnBoy manual for these mowers and many others is available for free download, maintained very helpfully by Toro.

Click to expand...

No, I was not aware that it could be adjusted. I've got the manual, I'll go through it again.

E: I just looked over the starter section for the D600s. I'll give it a whirl trying to reposition or reseat the mechanism tomorrow.

Lawnboy77 said:

The part numbers for the washer and bearing are:

Thrust bearing 252-76
Washer 252-80

You can Look up these parts by punching in the latest version of just about any F series produced after 1996. To get those numbers I looked it up by way of a 1996 model 10401.

Click to expand...

Do I need to take the mower apart to verify this "slop" or play in the bearing? I pushed up on the blade from the bottom and there is no play ie the flywheel didn't move more than a cat hair.

No you shouldn't have to take it apart to check for excessive end play. Sounds like your problem is not wear in the crankcase, good news! My guess now would be a wrong part installed, pinion gear, flywheel or pulley. I know there are few different types of pinion gear, pulley and flywheel combinations for the old Lawnboys, sometimes you can get away switching of parts, sometimes not, so I think at this point I would investigate the possibility of an incorrect part installed in the mix. I'm not really familiar with anyway to adjust the up and down aspect of that starter, but if for some reason the flywheel is defective and going on too far down on the crank I think that could cause your issue as well. Let us know what you find, this will be unchartered territory for me since all the other times that I have seen this it was due to excessive end play.

Re: Problem with 1978 5275 pull start mechanism

Whelp. I spent the morning and took this thing apart and I couldn't find anything wrong with it. I cleaned and pieced everything back together per the manual. The only thing I can think of is to try a new flywheel? I don't know why it would be sitting so low on the crank.

Very frustrating. I'm ready to toss this hunk of junk in the bin. Then again, the fault is really mine for trying to use a 40 year old mower.

Don't give up on that 40 year old mower just yet, once you get this figured out you will most likely have a great little mower that is probably better than just about anything that you can buy nowadays at the box stores. I think it's just a matter of finding out which part, or parts effecting starter engagement, got swapped out with incorrect part(s). The flywheel is a good place to start, the parts catalogue shows that your D-601 should have flywheel part number 681011 installed. If you can't read any numbers on the flywheel then you might could look at pics of D-600 flywheels on ebay to compare to what you have installed. I don't happen to own any D-600s, but I do know that the flywheels are not a 2-way interchange with any of the D-400s because of the larger cooling fins of the D-600. The starter components, like the pinion gear and pulley, are in some cases interchangeable with D-400s, not sure about the F series though. The good news here is that there aren't many parts that effect starter pinion gear engagement with the flywheel, so the process of elimination should be a fairly short one. I'm going to assume that you do have a model 5275 from 1978 and the title of your post, that says a "1978 5278" is just a typo?

EDIT: Do you have a lawn mower salvage yard around fairly close? I'm thinking that you being in Pennsylvania is a good thing, since it seems like I see so many good Lawnboys coming out of that state. There should be plenty of good D-600 parts around for cheap. The ebay link below should be the correct flywheel (681011) for your mower, it has a fairly good pic that might aid in comparison, or parts identification.
http://www.ebay.com/itm/Lawn-Boy-Fl...839500?hash=item1ec77c6e0c:g:KvgAAOSwiDFYQM7k

Re: Problem with 1978 5275 pull start mechanism

That is correct, the 8 is a typo, I have a 5275. The thing is, this happened gradually over time. It had been a great mower up until it stopped engaging at all. That number checks out with the ones I've found on ebay. I'm leery of putting someone else's used flywheel on from fleabay. But it looks like i can get one here for about $20 bucks. Thanks for the feedback.

I also have a 21" self propelled that is beginning to exhibit some of the same symptoms as the 19". It does not seem that this is a common problem but BOTH of my mowers are doing this? I haven't confirmed that the 21 is the same mechanism as the 19" but it feels the same. I can at least still get the 21" to catch and fire to cut the grass.

To be continued.

okay so it's just wear over time! and we know that the crank play is good, so now I think it almost has to be the wear that has taken place in the hole of the starter pulley p/n# 681896 and the steel pin portion of the cup and pin p/n# 681349. I think you have nailed the problem down to those two parts, and it probably wouldn't hurt to put a new pinion gear p/n# 607547 in there while you are at it. The D-400s have the same setup and I usually replace those parts when they start getting noisey on the retraction of the rope, but yeah if the wear went long enough I can see how that would literally raise the pinion gear when you pull up on the rope and the slop in the pivot point will force the pinion gear too high to engage the flywheel. I think we nailed down, now it's just a matter of finding those good used, or new pulley, cup and pin and pinion gear.

Here are ebay links to those new parts, don't know if you use ebay, but at least you get to see good pics of the parts. For folks like me who are stuck out in the middle of west Texas where no one has ever heard of Lawn-boy we rely on ebay for most parts that we need. I find they usually beat Toro on prices and many of these parts are NLA so Toro is not even an option anyway.

http://www.ebay.com/itm/Toro-Lawnbo...656958?hash=item3adbad167e:g:rTYAAOSwdGFYtxt4

http://www.ebay.com/itm/GENUINE-TOR...984851?hash=item1eafc5a653:g:TF8AAOSw2GlXJThJ

http://www.ebay.com/itm/272641616992?_trksid=p2060353.m1438.l2649&ssPageName=STRK:MEBIDX:IT

Hmmm. Is the shaft of the recoil starter bent? If I recall from my D400 8255, the recoil starter was not a real robust piece. Any way to try to shim it down, by placing say a small strip of aluminum foil on the top of the shaft. A few thousands, might enable it to engage the flywheel.

Regards

Jeff

Shim stock? I would suggest a piece of aluminum from say, a beer can.

Bob

I tried to shim it already. The end that is splined is not very long and the torque from pulling the starter pulled it up even higher as the shim made it unstable.

Those black nylon pulleys with the integrated worm gear came along in the mid 70s, before that they were made of cast aluminum. I have one D-400 from 1977 that has the black nylon pulley and I love how smooth and quiet those are compared to the aluminum ones. The only downside to that is they may wear much faster than the metal ones. It's kind of a catch 22 with that, if you don't lube it with some grease it tends to make noise and of course wears out from being dry. If you grease the cup pin then that attracts dirt which will also wear it out prematurely. I dunno, but I like the starter to be smooth and quiet so I choose to keep that pin greased with a light coating of wheel bearing grease, as well as greasing the main coil spring, if plastic is involved I use the white lithium based grease. I also put a little white lithium grease on the spring clip that drives the pinion, otherwise it makes noise. I don't think the Lawnboy manual even mentions using grease with those manual starters, other than to say don't use grease on the pinion gear. I think by design these parts are going to wear out somewhat quicker than the other parts of the mower, so why not at least make them work smooth for as long as possible, and it will obviously help if the engine is tuned right so that it starts with the least amount of pulls. One other spray lube I forgot mention is the dry film lube that leaves a teflon coating, that would probably be the best to use in there since it doesn't attract dirt and dust like the previous mentioned lubes. I spray that on the wheel bolts of the mowers with plastic wheels and it seems to work great.