OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Walk Behind Lawn Mower Frames Four Stroke Lawn Mower Frames Old Blue Base Rover Utility Mower

Hello All,
I am a brand new member and looking for guidance in a restoration.

I picked up the above mower at the local tip recycler's. It has Briggs and Stratton model 92502 engine - Type 0938 -01 and Code 78072809. First off, can anybody help me with understanding the Type and Code numbers please?

Secondly, I have quickly pulled the engine down a little - de-coked the head and valves, cleaned out the carbie. There is no spark. I have checked the condenser and points - neither look like they have ever been touched. I was thinking of replacing the electrics with a kit - coil, points, condenser, etc - but was wondering if there are options to this? Maybe an electronic device of some sort? Any info would be appreciated.

The mower is a pretty much flat base - no catcher chute or side chute. It is a deep blue - hammer finish. There is a small Rover sticker on the height adjuster, but nothing else to clearly identify it is Rover.

As the mower is complete, in basically good nick, has compression, this is going to be my first mower restoration project. Any help form others who may have or know of this type of mower would be hugely appreciated.

Many thanks in advance,
Jeff49 (Wallis)

A Warm welcome to you Wallis,

There's a few people on here who know more about these ones than myself, But I'll help you with what i do know.

The first two digits of the code, are your year, follower by the month, and day, So your engine was built on the 28th of July 1978.

The Type I dont know much about, its a more obsure reference to do with the coluor of the engine, etc.

The Model, 92502, would make it a 9 cubic inch engine (148cc) Vertical Shaft, with a Diaphram Carburetor (Pulsajet I Beleive) and a pnumatic Govenor (Air Vane) and Plain bearings, the starter should be a recoil starter on the top.

I'm sure our resident Briggs man, Grumpy, will be able to give you some more help with this one, and getting the spark working on it. In the meantime, is it possible you could get a few pictures up, as that always helps us work it all out!

Hi Jeff 49, in order to give you the best advice, could you please post a few pics of your machine to this thread?
There are often small differences between models that sometimes a pic will solve easily.
to the forum. I hope we can help solve your probs, mate.

Thanks Deejay and drjimbeam,
Had another look at it tonight. Rover Model 1507. I will take some pics and post them when the forum is online again in a day or two.
I sort of tested the condenser tonight with the multimeter, and there is continuity of circuit between the case and the centre post - I guess this means that the condenser is bad? Might be best if I replace it if I can, before going down the path of a new coil and points as well. The points look fine.

While I am here - any tips on how best to clean up the alloy flywheel?

I'll keep folks posted with progress. In the meantime, thanks very much for quick responses and the welcome to the forum.

Jeff49

Hello Mr Davis, and thanks for your post - it is a fairly old engine! Piston is still a good tight fit, no score marks on the bore - hope I can get it running.

Have just searched the forum for info about Joe Carroll's guide to fitting a breakerless coil to the mower, but couldn't find it, even though other members have made reference to it. Any chance of somebody directing me to the posts - or even giving a quick description of how to do it?

When I had a closer look at the coil, it is very rusted and some of the laminations are seperating.

And ah!! Also sprayed some WD40 into the pull-start clutch - just before I read the post about NOT doing that. So, how do I dismantle the clutch please?

Oh the joys of being impatient and a newbie.....

Thanks again, Jeff49

Let's start with a few details of your engine. Being a 92502, it is 9 cubic inches (148 cc, as Mr. Davis said), a third generation design, it has a vertical crankshaft and a VacuJet carburetor, and it has a horizontal-pull starter. You can find out much more than you will ever want to know about it, and other non-current Briggs and Stratton engines, by reading the relevant parts of the Briggs and Stratton engine overhaul manual, here:
http://www.tpub.com/content/recoveryvehicles/TM-5-4240-501-14P/css/TM-5-4240-501-14P_70.htm
The "70" at the end of that URL controls page number: 70 is the first page, and there are 224 more following it.

Concerning the specific issue of the ignition, suddenly having no ignition is usually due to the kill wire (wire from ignition module or breaker points to a contact under the governor, operated by the engine speed control) being permanently grounded due to something being bent or mangled somewhere. Whether or not it is the source of your current problem, if your old breaker-point style coil has rusted and delaminated, it may be time to replace it with the post-1982 Briggs ignition system, which they called Magnetron (a strange choice: a magnetron is the radar transmitting tube also used in microwave ovens as the source of Super-High Frequency radio waves. The magnetron was invented in Britain early in WW2, and was a significant new military technology since it made radar possible.) You should be able to get a second hand Magnetron ignition unit from a nearby scrap B&S engine, or a dealer if you know one who doesn't charge too much for commonplace old parts. You can get the official B&S bulletin on how to fit a Magnetron to a breaker-point engine here:

http://www4.briggsandstratton.com/miscpdfs/RNT/magnetron_retro-fit.pdf

Joe Carroll's way of doing this same job seems less complicated, but achieves the same outcome. Note that the Magnetron is a one-piece unit that replaces the old ignition coil. It looks just like the coil except it has a little black plastic bit added inside the iron part on one side. The black plastic bit includes a magnetic sensor that triggers when the flywheel magnet passes by the coil.

It is not necessary to fit a Magnetron - you can just replace your rusted coil with one from another contact-breaker engine. You will need to test or replace your condenser, clean the points, and set them to the correct gap of 0.020" at their point of widest opening. Also test the connecting wires to ensure they are not grounded due to the insulation getting cut through, and look for oil in the little tin box surrounding the breaker points. Oil usually gets in there by leaking past the plastic plunger that opens and closes the points: the other end of the plunger is inside the engine and is swimming in oil. If the plunger is letting oil past, you can try a new plunger and see if that stops the leakage, but if it doesn't, there is wear in the aluminium crankcase around the outside of the plunger, and it would have to be reamed and bushed to stop the leak. This is not worth doing unless you are a collector working on a rare engine: just forget it and fit the Magnetron.

Remember to set the gap between the coil and flywheel to the correct amount (about 0.010", or the thickness of an ordinary business card). An overly large gap will give weak ignition. Too small a gap may result in the flywheel touching the ignition unit.

Concerning your horizontal-pull starter, read this page of the repair manual:

http://www.tpub.com/content/recoveryvehicles/TM-5-4240-501-14P/css/TM-5-4240-501-14P_163.htm

The preceding and subsequent pages will also be useful to you in maintaining this component. The main issue is lubrication - the cavity where the balls sit, and the sprags that lock the balls, must be clean and dry or the balls will stick. However the center of the stationary part that includes the sprags, runs on the crankshaft extenstion, which is running at around 3,000 rpm most of the time so it requires some lubrication. Unfortunately unless the lubricant is kept strictly to the outer surface of the crankshaft/inner surface of the stationary part, it will end up spreading to the outside of the stationary part, get on the sprags, spread to the ball compartments, and gum up the works. B&S therefore say use just one drop of good quality oil. If you ever hear a shrill screech from your engine, stop it immediately and service the starter (clean it and oil it). See why I prefer the vertical pull starters?

If you have any problems in following all this, or there are other issues with your engine, just post them in this thread and we'll see if we can help further. Reports on progress, and some pictures, would be useful in making this thread a help to other members.

Hello Grumpy,
Thanks so much for all that information, especially re the Magnetron and links to the service manual relating to the relevant concerns I have at the moment.

I will hunt down a Magentron type coil from somewhere in the next couple of days and see how it goes. Might tackle the clutch thingy tonight and remove the WD40. I have noticed that as I screw the clutch housing down onto the crankshaft, the square shaft becomes tighter and tighter to rotate.

I will also get some pics up as soon as I can, and myabe start a new topic on the restoration project. I think what I want to do now is put the mower back together, get it to run, then strip it down again and do a thorough clean and paint job. Currently have the cutter palte in an electrolytic bath to remove the rust and free up the blade bolts.

Will keep you posted, as they say on forums these days!

Many thanks again for your time,

Jeff49

Jeff, it sounds as if something is out of place in your radial pull starter, if it jams when you tighten the thread that holds it on. If you just follow the manual, and make a couple of checks along the way, you'll find it easily enough. Make sure the balls are not out of position - if in doubt, assemble it without the balls, and see if that makes a difference. If all is correctly assembled, it won't make a difference, it will be free with or without the balls. I vaguely recall having the same problem the first time I put mine together, but it was a simple error. Don't forget to inspect the tips of the five sprags for wear.

I have just checked my record, and relised that the Rover Baron 45 I will soon be restoring has a 92502 as well, So it would be great to see some pictures of yours, and I am quite excited to follow your restoration story!

I'll pop up a thread for mine too when work begins, its a Silver 1977 model.

You can catch a glimpse of it in THESE photo's, it's the second one from the right.

Mr Davis,
Quite a collection there! And they look great!

An update: I dismantled the radial pull starter clutch last night - full of gunk (not made better with my WD40) which I cleaned out and the starter now spins nice and freely with a delightful rattle of balls bearings running around inside.
Also took some pics which I will post tonight when I have time to work out the picture posting process (alliteration there).

Took a couple of pics of the de-rusting process as well. The plate that carries the blades has come up like new - lovely dark steel and not a speck of rust. If people don't already know about the electrolytic process, I can provide details.

I would dearly like some tips on how to safely clean the alloy bits - head and flywheel especially.

Once I can get a an hour to sit at the computer, I will start the restorationn thread - in the meantime will make every effort to post a few photos tonight.

This mower is becoming habituating!

Jeff

Jeff, cleaning aluminium can be done either mechanically or chemically. The most important point is to distinguish between sealing surfaces and other surfaces. Sealing surfaces - which just about always have gaskets between them - have to be kept smooth and flat, so both wire brushes and corrosive chemicals are out. I usually scrape them, but scraping aluminium has to be done carefully because the metal is so soft. Do not just put, say, the cylinder head in a cleaning bath, because it will probably cause pitting, including pitting of the sealing surface. You can brush it on, though, and wash it off, or you can use a wire brush, on the non-critical surfaces.

You can look forward to a lot of fun with your 92502. It is generally the same as my favourite small Briggs, the 92908. The differences are that the 92908 has a PulsaJet carburetor instead of a VacuJet (the PulsaJet has a fuel pump while the VacuJet relies on venturi vacuum to pull fuel up from the tank), and a vertical pull starter (like a car starter, it only engages with the ring gear around the flywheel when it is being operated - the rest of the time it just sits there completely inertly) instead of a radial pull starter (which has a couple of rather iffy features such as the plain bearing on the crankshaft, and the sprag system for locking it). Those Briggs engines are smooth, reliable, easy to repair, and parts are usually cheap and plentiful. (The Honda engines tend to have the first two features, but not the latter two).

Sounds like its all been covered.


Did not see anything about valve clearances. Be sure and check them.
Also slop in the guides. Not much you can do about that.


Swapping the coil to electronic is easy. You can even just snip the wires and leave the points and condensor in there. No need to pull the flywheel off (again).
Or set the wires aside and use the electronic to test run the motor. Then set it back up with the points.


I do beleive that i have a rover here the same as the one you are talking about. The one on the left

Gee thanks, Rodeobob!
Yep the one on the left is the same as mine - nice to see your other mowers too.

When I pulled the head off the other day, I also pulled the cover plate off that accesses the vlave stems and springs. The guides seemed to be pretty firm - at least there was no slop in the stems. The valve heads were pretty coked up, but I persevered with a hard plastec scaper and got most of the gunk off the seats and faces. I may need to put some grinding paste on the seats and cut the faces/seats in. Just want to get it running first if I can - of course I may need to do the valves for that to happen!

I will be off to do a round of the Bendigo tips and mower shops over the weekend to see if I can pick up a cheap Magnetron type coil. Will also get some time at the weekend to start the renovation thread and put the pics up that I have taken.

Thanks again for the photo of your mowers.

Jeff

Scrap yards are good too.
Just make sure youve got your own tools with you.


Cheers, Bob.

Ah, Kids!
All my pics were on the camera - not yet on the computer - camera had to go to Melbourne Friday - all my pics got deleted!

Oh well. Took the engine to the car wash today and gave it a good scrub down. Have the mower base in the electrolytic bath getting the rust off, have painted a few bits and pieces, and haven't had time to search for a coil yet.

I am an optimist, and figure that the mower will run when I get it back together, so might as well clean it, paint it, get the bits I need, and hope for the best after it is reassembled.

Well,
Picked up a Magnetron this morning from the recycle yard - $5.00 - and the guy threw in the rest of the mower as well!! It was caked with dirt and oil, but cleaned up OK and I will have to wait now until the rest of the mower is re-assembled to see if it will throw some spark.

Can't recall offhand the engine type - 92806? 92608? - anyway it is a 1984 model. If anybody is looking for bits for this engine, I have them to give away. The vertical pull starter is in really good nick, and the rest of the engine is very dirty but I am sure it has bits that might be useful for somebody.

The base is still in the electrolytic bath but is starting to look great as the rust flakes off. With any luck I wil pick up a new diaphragm for the carbie tomorrow, and may have the mower running by next weekend.

I will take some more pics of what I have done, and post them.

Jeff

Jeff, you said your engine is a 92502, which means it has a VacuJet carburetor, and does not use a diaphragm between the fuel tank and carburetor, just a gasket. I suggest you check things out before you buy a diaphragm that you may not be able to use.

Your "new" $5 mower's engine is probably either a 92508 or a 92908. The third number tells you the type of carburetor - if it is a 92908 it has a PulsaJet carburetor, and uses a diaphragm instead of a gasket, between the tank and carburetor. The PulsaJet has a fuel pump, the VacuJet doesn't. The final number is 2 for a radial pull starter and 8 for a vertical pull starter. You said it is vertical pull, so the final number will be 8.

Hi Grumpy,

When I pulled the carbie off the tank, there was a rubber gasket betwxit the twain. Top side of the gasket had a hard copper linkage which hooked into a link inside carbie body, the underside had a thin coil spring which was attahced to the gasket and the bottom of the spring sat in a smalll depression on the top of the tank. I just assumed this was a diaphragm.

Yes, the cheapie motor is a 92908. I guess there are thousandds of these around, and nobody would really be interested in my engine or its parts.

Thanks for the tip-off!

Jeff49 (First 4 characters are model designation, last two characters year of production).

I'd take the whole of whats left of the motor but postage would be too much, oh well I will find a new source of mowers one day soon!

Hello Joe,
I will check around on post or freight prices for you - might be a way to get the motor to you. Other option is I have family in Echuca - seed grading business - who sometimes go up your way - might see if they are heading up there any time soon. Will keep you 'posted'.
Jeff