OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Briggs & Stratton Engines Briggs & Stratton 3.5 over revs

Sorry, I initially typed the wrong number. It should be 98902 2064 P1 01091954

Ah, 98902 seems better to me, Cheers Sparker!

That means it was made on 19 September 2001, so I don't know why the coil looks like an old one to me. One possibility is that it doesn't have the original air cowl. Does the starter cord pull up vertically or horizontally, sparker? Pre-Magnatron vertical crankshaft engines had vertical pull starters. (So did the first few years of Magnatron ones). If the air cowl is correct, I'm unfamiliar with the ignition coil it has - which isn't important but may be interesting.

Post-Edit: The coil is a Magnetron, as noted in a previous post-edit. And I should have known the engine had a conventional recoil starter, not a vertical pull. For normal recoil, the model number ends in 2. For vertical pull, it ends in 8.

Meanwhile I'm glad that is sorted out. It is nothing unusual with second-hand mowers, sparker, for the problems to be due to the tenant's improvements. It is one of the things that keeps us on our toes.

Grumpy, even if it does turn out to be something you are unfamiliar with, you still managed to find the fault and get him running! Good Job!

Sparker, if you could help us with our curiosities of your engine, is it possible you could post a few pics of the whole mower, and a few of the engine from the sides, back and fornt?

Sure, no problem but you'll have to excuse the crappy paint job. I was really disappointed there. Normally I'd use a hammer finish spray paint. This time I thought I'd use some old paint i had lying around which was close to the original blue but it is far too soft and scratches easily. here ya go!-

Thanks for that sparker, Just had a look through my records, and it seems i have a 2003 Victa Charger with a Briggs 98902, so when i have the chance, i will get a couple of pics up of its linkages, for reference skae.

However, even if my mower tells a different story, from the sound of it, Grumpy's advice has served you very well, so i would be hesitant in changing anything unless further problems arise.

I'll get some photo's up when i can, i may have already posted a thread about mine, if i find it, i will add it to this.

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Heres one i forgot i had picked up the other day:



And here is the charger, Although its not a great angle, the second pic in this thread Seems to show only one spring, confirming Grumpy's comments.

I will get some better pictures up here at some point.

Grumpy, you have got me very curios about the 80's minions, could you post a few pictures in the gallery if you have one?

On the contrary, I think I can see a second spring in the hole near the governor cover. Doesn't matter anyhow now, as you say. That mower is identical to mine except for the colour and name. Even the stickers are the same.

You may well be right, i missed that little line there.

But as i said before, I'm fairly new to brigs, This is really grumpy's field, and wether his fix is factory original or not, it sounds like it has worked, which does not surprise me, He knows these engines pretty damn well (apparently even the ones that he dosent know )

Unless you are going for perfect original (and I'm yet to see somone keen on doing a full detail resto on a 2001 Vatage!) then yes, if it works, then it works!

You're absolutely right! I spent two days trying to figure what the hell was wrong (and I still don't know for sure) but it's working perfectly now as a result of Grumpy's thought train, and that's all that counts

Ty, I'll have to get my spare mower out of storage under the house to take pictures of its Minion carburetor. Meanwhile here's some technical detail:
http://www.tpub.com/content/recoveryvehicles/TM-5-4240-501-14P/css/TM-5-4240-501-14P_105.htm

I'm still not clear on that coil in sparker's mower, it looks like a pre-Magnatron one, but it can't be because it would require the base engine to have points.

My current suspicion is that sparker's engine had a home-made governor link that simply refused to pivot at the butterfly end, and jammed the linkage.

Thanks for that Grumpy, no rush for the pictures, just next time its convenient.

I will make sure to get a look, and a few pictures, of the coil on mine, and see if we cant find some answers.

With there later electronic Ignitions, have Briggs moved to a transitorised coil, or do they use a seperate coil and ignition module.

This looks like it could be an electronic ignition module to me:



What is it?

Yes, it's electronic. There are not any points.

Ty, Briggs moved to an all-in-one ignition unit (Magnetron) in 1982 and haven't used points since. The unit replaced the coil - it was a coil with a little electromagnetic sensor attached to it, to trigger the ignition as the flywheel magnet passed by, so no points were required. It can be fitted to older engines without modification of the engine. I'm not familiar with the appearance of the later electronic units - the original Magnetron was electrically rather crude, though they seem to have been reliable. sparker's unit looks just like the early coils, but doesn't seem to have the external Magnetron sensor attached.
Post edit: the ignition unit in the picture is a Magnetron, and the electronic unit is the black part which Mr. Davis has circled.
Perhaps they made the device more compact. Anyway, all of them look the same: same coil, attaching to the engine in the same place, and in the same way. The only change was in how the coil primary was triggered.

Ok, that's a bit differend to what I'm used to seeing, When Victa moved to electronic ignition, they used the same coil, but replaced the points with a module that controlled the timing. I imagine with the Victa module, it operated by the pulse from the coil itself, as the magneto passed. It was certaily not close enough to the flywheel to sense the movement itself.

In recent years, this moudule has been moved, and is now cast inside the form of the coil, creating a square plastic lump. i have also seen this with a number of brushcutter coils, thoug i imagine some of them would also use the system you are describing with briggs.

I could specuilate that the victa version is cheaper, as it seems to be adopted more widly by manufacturers as they move to China, however, the above engine pre-dates Rovers move to china i think, so that would not reflect on it.

I'm getting really curios now, so tonight I will try and check under mine, hopefully what i see there is the same, and i can pull it off and get some good shots and any markings noted, and post them up.

Ty, these 3 pictures are of my 3 May 1983 B&S 92508. It has a plastic (Minion) VacuJet with automatic choke, and the original version of the governor we have been talking about in this thread.




The third picture shows the coil. It is a very late points-type coil - I thought they changed in 1982, but it appears it must have been a bit later.
Post-edit: The coil in the picture is a very early Magnetron

Thanks for that Grumpy, I'll have to have a look through some of my recent donations from that era, Looking at the records i have with me, i dont have a 92508, but I have a few models from 1980 - 1988, so maybe one of thos may have one.

Since i have branced out, I have been trying to get my hands on as many different engines, and carby's as possible, to get my experience up and work out as much about the engines, and thier histories as possible. So if i dont have a Minion yet, i now know what to look out for!

With the coil, is it possible there was an overlap, maybe they started relesing the magnetron on some models in 82, and ran the points out till the next year on others?

Ty, a 92908 (i.e. basically the same engine with a PulsaJet instead of a VacuJet) from the same period was likely to have a carburetor made from Minion plastic, it wasn't only the VacuJet.

On the introduction of the Magnetron breakerless ignition, note that there is an official B&S way to retrofit these to breaker-point engines:
http://www4.briggsandstratton.com/miscpdfs/RNT/magnetron_retro-fit.pdf
Joe Carroll's way seems quicker and easier.

I have only found vague references to the changeover date to Magnetron on the internet. Some say 1982, some say it was mostly done by 1983, and some say it happened progressively over quite a few years (this last assertion might have been referring to changing the large industrial models to breakerless ignition, I think). I fully expected to see a Magnetron coil on the 92508 in the pictures - I've never needed to take the cowl off it before today. This diagram shows where the Magnetron module should be visible (the coil installs with it underneath, toward the engine, not on top, where it would be easy to see):

In the third picture in my previous post you would be able to see it up near the air vane, on the opposite side of the coil from the HT lead. And I agree, that was the object you circled in red on sparker's coil: it appears to be a standard Magnetron, just like in 1983. Maybe I should get my glasses replaced.

Well, Excluding a few from the late 90's and the last decade, I have (Going by by records it this point)

-1981 93508
-1980 92908
-1977 92502
-1989 100708
-1975 100902
-1985 92908

there is also one more, i havent noted its model yet, but i can remeber it, it's a 197s Rover Pedigree with the original 148cc Briggs on it.

I will look for the Minion when i get a chance, and as i go through restoring the above engines, i will document the restorations in a thread. (Looking forward to the 75' 100902, thats the Rover Super Four 21, From Redeye)

I know this is an old topic but I have a Pope mower with the minion plastic carb with 2 govenor springs.
Motor on this is a 098902-2030-B1
I have attached some pics on how the springs are meant to be connected.
Sparker's second spring seems to be connected incorrect and is overstreched causing the over revs.
Pics 1 & 2 are with govenor closed at 2 throttle positions.
Pics 3 & 4 are with govenor wide open using a screwdriver to actuate govenor arm.

Here is the B&S doctrine on how the single and double spring governors should look:



AS you can see, Fig 93 shows a dual-spring 98902 and Fig 96 shows a single-spring 98902. It seems both versions exist. In the older series such as 92908, only single-spring versions exist.