Briggs Radio Rod Build

[JTSpeedDemon]

Well, might as well start a build log for this thing, but it'll be a slow build due to the fact that the calendar won't slow down for my Build Off project, the Hothead.

Anyway, down to the details.
I've got a hot rodded Radio Super wagon that I picked up at Pate Swap Meet 2019 for $60.
I also have an old 3 HP Briggs and Stratton flathead that I got for $30 off Craigslist.
The two are fated to meet.

First Update:
Gas tank has been soaking in vinegar overnight, I need to drain & finish cleaning it today.
The engine has no spark at the plug due to a dead plug, so a new Autolite 295 is on the way and should arrive on July 12th.
I know the coil/magnet are good since I've been shocked twice by the system, but as usual, the spark plug is kaput.
I still need to clean/fix up the Pulsa-Jet carburetor, because given the condition of the gas tank, the carb is probably filthy.
Once I have a runner I'm going to load up this engine with a ton of performance mods, but unfortunately my options are limited due to the fact that the 3 HP flatheads are commonly overshadowed by their 5 HP, 13 Ci big brothers. The 5 HP flathead actually has even more aftermarket upgrades on the market than even the clone/Predator 212 engine.
Thanks for looking!

 

[JTSpeedDemon]

Eeeewww!!!


THAT, is the horrifying results of the vinegar bath, and one can of each of the following:

1. Carb Cleaner
2. Brake Cleaner
3. Electrical Parts Cleaner

But at least the tank is finally clean!
But eeeeewwww, that sediment...:arf:

 

[Crash87]

Looks like a cool build man!

 

[Hellion]

THAT, is the horrifying results of the vinegar bath...

Did you dunk the fuel tank in that? How big is that whatchamacallit?

Turned out really good, or good enough. How are the fuel pickup tubes on the carb and the screens on the ends?

 

[BigWes]

You can mix a solution of 50/50 cleaning vinegar and hydrogen peroxide to clean certain things Spunkwagon...just do some internet research before you use it as it can become extremely hazardous if you aren't careful with it. It can also destroy certain metals and finishes as well. It can be very useful in the right situation though. Works very well for removing lead deposits from my titanium baffles

 

[JTSpeedDemon]

Did you dunk the fuel tank in that? How big is that whatchamacallit?

Turned out really good, or good enough. How are the fuel pickup tubes on the carb and the screens on the ends?

I filled the fuel tank with straight vinegar and let it sit for 12-15 hours. It didn't really remove much varnish, but it did seem to loosen it up quite nicely.
I just used the drain pan to, well, drain. All the old contaminated fluids and stuff ended up in there thank goodness.
The vinegar stank up the garage for a bit. Annoyed my older brother.
I haven't dug into the carb yet, but I'm mostly waiting on a spark plug, because for all I know, the carb is fine.
Should probably clear out the pickup tube at least though.
The tank ended up almost perfect. There is some REALLY sticky residue in the tank, but it's now 98% bare metal. And the residue that is there, wouldn't come out after being sprayed straight on by solvents, so I'm not worried about it coming loose and clogging stuff up.

Oh yeah, about the actual chassis this engine will go on, I should say that I will at the very least redo the rear end with a live axle, since the current axle setup is completely unsuitable for an engine. I will probably also have to redo the steering system.

 

[420Racer]

Cool dude I'll look forward to seeing this done!

 

[JTSpeedDemon]

Ok, wow. I am baffled by this little engine.
I know it's not the spark plug since I swapped in the working plug from my 5 HP flathead and it didn't spark.
I took off the coil and cleaned the mounting points, as well as what I think is the ground(wire/terminal in 2nd pic). I also properly reset the coil gap, and even greatly reduced the spark plug gap to try and get it to spark.
No go.
It could be just a worn out coil, but before I resort to replacing it, what do these wires do?(see pics)
What is the little one going behind the flywheel, and the red one and the one next to it?

 

[anickode]

Judging by the apparent age of that engine, you probably need to pull the flywheel and clean and set (maybe replace) the breaker points and condenser.

Or buy a magnetron coil for it to eliminate the points and condenser.

---------- Post added at 10:49 PM ---------- Previous post was at 10:36 PM ----------

FYI breaker points and condenser were used in older engines (both magneto and ignition coil) and utilize the principle of inductive kick to create the voltages necessary to fire a spark plug.

A single magnet moving past a single pole generator creates a DC voltage. Not enough voltage to fire a plug though. A breaker point essentially shorts out the windings, and kind of lets the coil "wind up" so to speak and build voltage in the condenser (capacitor), then the breaker point opens the circuit, creating an inductive kick which produces a high voltage surge sufficient to fire the spark plug.

The operation is a bit simpler to understand with an ignition coil setup, but essentially the same.

 

[JTSpeedDemon]

Ok, so I need to take off the flywheel and check clan the ignition points I apparently have. Got it.
Thanks for explaining. Is the points system to help it fire due to the generally low HP of this engine?

 

[Randy H]

Here's another option. I think you should still investigate your points and condenser. A good cleaning might get you running. If you need new parts. The kits do work great. Fast install.

This might be BS, but I have heard the magnetron kits advance the timing. Heck if you can come up with a timing light and a redneck degree wheel. You can test that theory.

Of course if your coil is bad this won't help you.

By the way I didn't check any part numbers.
https://ebay.to/2zPRV9H

 

[JTSpeedDemon]

So the points system is called a Magnetron system?
Don't worry, parts numbers wouldn't help anyway, as the blower housing is from a vertical shaft engine like a lawn mower!

 

[Hellion]

No no no, the points-less ignition is called Magnetron. That’s the one you want. But I’m running points on several engines around here and I like it. It’s a dying art being able to gap your points and do a basic ‘old tyme’ tune up.

But I digress.

 

[JTSpeedDemon]

I'll just keep the points system.
I'm not gonna wuss out and do the easy way of putting a Magnetron on it, instead I'm gonna figure out the points system.
It adds to the vintage charm of this thing. Besides, my Haynes manual has instructions for servicing points.

 

[Hellion]

Outstanding!

How’s the project coming along, dude? Any updates to share?

 

[JTSpeedDemon]

Well, not much other than engine problems.
in my head I'm figuring out how to get power to the rear end.
I plan to have one jackshaft, going to a live axle, both on pillow blocks to keep things simple.
I think the rear tires will be 13/5x6 ribbed tires, but I'm not sure.

 

[Randy H]

I'll just keep the points system.
I'm not gonna wuss out and do the easy way of putting a Magnetron on it, instead I'm gonna figure out the points system.
It adds to the vintage charm of this thing. Besides, my Haynes manual has instructions for servicing points.

Well there is wussing out and there's making intelligent decisions.
Sure for the sake of knowledge play around with the points and condenser.
If you need new parts though it will cost about the same to go with a much more modern, more reliable yet ancient system.
Likely easier starts, better fuel economy as we as overall increased performance.

You can file points, a stop gap temporary fix. Condensers can fail at any time. Like any electronic component. But less reliable than most.

On the other hand points are dirt simple to set. If you can get the flywheel off and locate the appropriate feeler gauge, you stand a pretty fair chance of project success. Even using different condenser values to balance wear on the point contacts isn't complicated.

That's all my opinion, and cold hard facts lol. Here's PDF for the sake of knowledge.

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

Good luck on yer projects.

 

[anickode]

The major downside to points on a small engine like this is the need to remove the flywheel to get at them. They also tend not to work so well in an over-rev situation, since the mechanism is similar to a valve rocker, the points can float and cause them to cease functioning and excessive wear, etc. So if you're planning to hot rod the engine, upgrade to a magnetron coil.

 

[JTSpeedDemon]

Ahh, Ok.
Since it's a finicky pneumatic governor that I can't quite figure out the linkage for, I will probably just take the air vane assembly off and rev it to valve float, but not too much redline.
I'll try to get the points system running, but if it's too finicky, or just dies after a while, I'll do the Magnetron retrofit.
Thanks for the help guys! Really helpful!

 

[JTSpeedDemon]

Update: It runs!!


WOOHOO! I popped off all of the flywheel stuff, cleaned and readjusted the points, and I finally got this 3 HP flathead running! On gas, choke on or off!

The points were dull and a pretty deeply pitted, but after filing them down to a chrome shine and adjusting the gap to 0.02", it runs like a dream!
It sounds pretty gutsy too, even with the muffler!
It currently doesn't have the pneumatic governor in, but I'm gonna reinstall it since I don't feel safe revving it past 3600 with the pretty shot flywheel side bearing it has.
I know, I know, pics or it didn't happen, but don't worry, I took pics and video!

---------- Post added at 04:59 PM ---------- Previous post was at 04:49 PM ----------

Oh yeah, when I was tightening down the starter clutch(incorrectly ) it came apart, so while I was in there I cleaned it up and everything, so that's good, because it was pretty gunked up!