magneto on older briggs. Possible?

[Ponduke]

Hello, I used to post here occasionally a few years back. Back when I mostly had the occasional question for SmilinSam regarding an Allis-Chalmers 912 I bought from him on eBay in 2001. The tractor has performed very well for me over the years since and I am a big fan of these fine garden tractors. Well, now I've went and screwed up and need the expertise of this board for a bit of wisdom. I purchased an electronic ignition for the motor as I always had to readjust the points every couple hours of operation for whatever reason so I figured I'd eliminate the points and coil all together. I give the motor number off the shroud to the parts guy and he brings me the right electronic ignition for that motor. It's a Briggs horizontal shaft 16 hp motor. According to the shroud, it was made in 75. I get the shroud off and realize there’s nowhere to mount the new magneto. I call the shop I bought it from and he says it should mount right up to where the coil was. Problem is, the coil is the slightly smaller than a beer can canister type mounted outside the shroud on top of the motor and the points are outside the motor too, under a little cover cap on the side. The guy at the shop was perplexed as the part number of the motor says that shouldn't be the case. We finally concluded that the shroud on my motor that has the model numbers was from a different motor and my motor is older than the 1975 model that is specified on the shroud. Now, what can I do? Do I give up and assemble it all back together and accept that I must tweak the points every so often or it there a way to retrofit the magneto to this older motor. The flywheel does have the required magnet on it and the shroud does fit perfectly so the motor should be pretty similar to the 1975 model and the magneto radius does match the flywheel. I was hoping there might be a bracket I could use to mount the magneto that would locate it properly on the flywheel. Is that possible? Is there anywhere I can find the real year and model of this motor since the shroud is wrong? What to do, what to do?… I hope my questions make sense. Thanks in advance to anyone who can shed some light on this. Brian Brian Mann

[UCD]

Sounds like it was converted to coil ignition with external coil. Maybe Sam can tell you if he converted it.

[HubbardRA]

A 12 Hp Kohler from 1975 would have been a K301. These came from the factory with an external coil and did not have a magneto. I am not sure when they started using magnetos on the one cylinder engines, but it was much later than 75. My AC716H was built in 1977 and it still used the points w/external coil type ignition. I would say that your small engine technician is mistaken, and that engine never came with a magneto. Why not use a capacitive discharge ignition unit? They use the points only as a switch, so the points will not burn. These are an external bolt on. Also, if you have to clean the points every two hours, you most likely have a bad condenser. A condenser that is out of spec will cause the points to burn quickly. Also using an automotive coil without a ballast resistor will cause the points to burn. The factory Kohler coil had an internal ballast resistor. The coil may have been replaced with an automotive coil. They both look similar.

[UCD]

Rod He states that it now has a 16 hp Briggs and Stratton.

quote:

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Originally posted by Ponduke
It's a Briggs horizontal shaft 16 hp motor. According to the shroud, it was made in 75. Brian Mann

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[HubbardRA]

Thanks Maynard, I just looked at the 912 and the 1975 engine. Overlooked B/S. The comment about the condenser and the ballast resistor still hold true. Also, if I recall correctly, the magneto that I removed from my 243431 when I converted it to battery-coil ignition, was mounted onto a secondary bracket which in turn mounted to the engine. I think I still have that. I will try to remember to look this evening.

[Ponduke]

Thanks Rod, for that info! I'm really not too much of an expert in small engines as my posts likely illustrate. Are you thinking the breacket you're going to look at tonight might be what I'm missing on my engine? I'm also not familiar with a capacitive discharge ignition unit. That might be an option if I can't make this magneto work (that is what an electronic ignition is right, a magneto, right?) I only know it is a 16 HP Briggs with the automotive type coil. My wife is after me to get the yard mowed soon so I need to do something soon as I currently have it in pieces in the garage!

[HubbardRA]

A standard automotive coil without a ballast resistor runs the full 12 Volts to the coil. With a ballast resistor, the voltage is dropped to about 6 Volts and the current going thru the points is also lowered. A capacitive discharge system uses the points only as a switch. A large capacitor in the unit is charged up, and at the time when the spark is needed, the capacitor is discharged thru the coil. There is almost no current going thru the points, so they cannot burn. A CD unit is just a box that wires up to the battery and the points. I used them on automobiles before everything went to electronic ignition. They are still available. Do a google search for Capacitive Discharge or CD ignitions. Here's one, go there then click on ignition systems. http://www.universal-co.com/index.aspx

[Ponduke]

Well, that looks like an interesting option, but first I wonder if there's any way to retrofit the electronic ignition I already bought for it. Surely there must be a bracket or something. And is there any way I can determine the model of my motor? Thanks again for all the help!

[SteveP]

I just went through this. Mine was a 32640 made about '73. I put in a briggs part number 398811. See post [url]http://simpletractors.com/club2/topic.asp?TOPIC_ID=81444[/url] I would think it should work on your also. It had to have a coil on there some where, aint so

[Ponduke]

Steve, That part number you gave me for the ignition coil you said should work on mine is the coil I already have! The problem is I have nowhere to mount it. The existing coil, as I said, is the canister type mounted external of the shroud on top of the engine. I'm hoping to figure out a way to mount that 398811 coil that "should" work.

[DMedal]

Ponduke, if possible for you, pay the $10 and post pictures. We could take days/weeks off this process. show us what you bought, what you have. just an idea. It sure has paid off for me in learning and $$ saved on unneeded parts. -Don

[Ponduke]

O.K. When I get the chance I'll see if I can get some pictures posted to clear things up.

[HubbardRA]

Ponduke, I remembered to look tonight, and I could not find the old magneto that came off my engine. Sorry, but I can't tell you about the mounting method.

[Ponduke]

Thanks for looking anyway! I went ahead and put the motor back together over the weekend and am reverting back to using the existing coil and points as I needed to mow some and couldn't wait, so no pics. It runs fine really I was only hoping to install the magneto as I have to adjust the points every so often as I stated. Next time I get some time I'll consider some of the options that were suggested in this thread. Thanks again, Brian

[simplejim]

someone has changed it to an automotive style coil.the original should have been under the shroud right above the flywheel held on by two bolts.your new ignition should bolt right there in place of the original coil.

[Ponduke]

Thanks for the reply simplejim. That's what I thought too, except there is no where to mount it under the shroud. My dad and I (he's installed a few himself and knows small engines pretty good) both looked and there is no way to mount it without some sort of bracket and we don't know where or how to find one.

[simplejim]

that is odd!dont believe i have ever ran across an older briggs like that.im lost too then.

[SmilinSam]

I just got around to reading this thread. I think that engine came out of a 1975 Homelite T-16 if I remember right. It was already switched over to the battery ignition setup like Kohler uses when I got it. I never had the shroud of I dont think , so its possible whoever had it before and did the switch unbolted the magneto mount that goes on the bearing plate. Tell you what, I have a 14 HP cast iron briggs here that runs good but smokes like a barrel of burning tires. I can get the shroud off this weekend and see about getting the magneto coil mount off and see what the shipping cost would be to you. That engines been sitting here too long anyhow and I wont be fixing it anyhow.

[SmilinSam]

One other thing now that I think of it, I had another BRiggs in here a long while back that also was already setup for battery ignition. I went through the effort of putting it back to the regular magneto and points. Wouldnt even run then. After much aggrivation we found the flywheel had partially sheared and thrown the timing off. I'm saying this just in case , because with used engines that havebeen changed around you dont know the resons why till you dig into it yourself. The one you have may have been altered for the same reasons, or maybe it just had a bad coil. Whos to say at this point. I'll get back to you on the mag mount later this weekend. Sam

[Ponduke]

Thanks Sam! I was hoping to hear from you in this post. I found out I can't return the magneto because the store won't take back electronic parts so seeing as I'm already out the 50 dollars it cost me, I'd sure like to try and use it. Just let me know the shipping cost if you manage to get that mount and I'll get it to you right away. If it ends up not working for the reasons you state or some other reason, I will have at least tried. As I said earlier, I love that little tractor. It has ran nearly flawless for me since I've had it (other than the earlier mentioned points adjust every so often) and I use it A LOT!! Of coarse with that 38" tiller attachment that came with it, every spring I'm in demand by all the neighbors wishing to have their garden beds tilled. It still amazes me how good it does.

[SmilinSam]

Did the guy that sold you the electronic ignition say anytghing about having the flywheel re-polarized? I dont know the details but there have been other posts in here talking of it one way or another. Can Anyone else add anything to that issue?

[SmilinSam]

I have the mount ready to ship, just need to have a street address e-mailed to me to send it.

[Ponduke]

Thanks again Sam!! email is sent. Brian.