Amphibious Tractor

Calling this one the 1/2 Ton Amphibious Tractor.  Tore apart the old ATV earlier this year for parts.  Started this build early October, I think this machine might actually get a coat of paint!









Colder weather and heavy winds put a slow down on construction but I might take it for a short romp when it snows lol.

Looks pretty freaking wild!

Holy Tank!

The return of Frostypaws!

Amphibious tractor?!?! I'm with Crazy Carl and call that a TANK!

Well I got the throttle hooked up and a temporary mower seat mounted.  So the Yoda starts up fine in the cold, but I am running into stuttering issues during hard acceleration.  

Thinks I checked:
-Running at operating temperature
-Timed @ 8° BTDC, spec'ed to service manual

I wonder if there is something wrong with the vacuum advance?  I will do some more tinkering and see...

I suppose if the vaccuum advance isn't working it would have a hard time responding to fast throttle with out snuffing itself out, other that that maybe it's a mixture problem?

On my sisters Pontiac grand prix , it will not allow the rpms to go over 4000 unless you put the transmission in gear and drive , but when in park and you try to rev it past that point it cuts out like this engine is doing . Think its called a rev limiter or something.

To get that stumble on acceleration, would be one of a couple of things.

A vacuum leak. Unmetered air entering intake which is leaning out the engine.

Vacuum advance hooked up wrong on distributor. Should be hooked up on the carb to a vacuum port to where the port is not sucking vacuum at idle, but when you speed up motor a little this port will suck vacuum, and at wide open throttle there is no vacuum. The vacuum advance is there to save gas when the engine is at cruising speeds only. If you don't know which port is right, then you can just plug it, the engine will actually have more power with it not working but will use more fuel. Marine engines don't use a vacuum advance for the power, might be good if you didn't either for the extra power. Your distributor needs the weights in it to advance timing though. if the distributor don't have the weights in it to advance the timing, then you need to change it to a distributor that does for the engine to run right.
Accelerator pump in carb not working right. Look down the barrels of the carb, looks like a 2 barrel to where both barrels are running the engine. Tap the throttle just a little a couple of times and you should see the gas squirting in both barrels. If not then the accelerator pump is not working right and is leaning out the engine on acceleration.

Don't know the year of the motor, but the early to mid 80's engines, some of them used computer controlled carbs and distributors, if you got this setup, it would run way better with an older carb and distributor on it that don't need the computer.

its badassw but i dont think it counts as a tractor.

Sure it does! Just not a lawn tractor. HAHA... sweet build.

prancstaman wrote:

To get that stumble on acceleration, would be one of a couple of things.

A vacuum leak. Unmetered air entering intake which is leaning out the engine.

Vacuum advance hooked up wrong on distributor. Should be hooked up on the carb to a vacuum port to where the port is not sucking vacuum at idle, but when you speed up motor a little this port will suck vacuum, and at wide open throttle there is no vacuum. The vacuum advance is there to save gas when the engine is at cruising speeds only. If you don't know which port is right, then you can just plug it, the engine will actually have more power with it not working but will use more fuel. Marine engines don't use a vacuum advance for the power, might be good if you didn't either for the extra power. Your distributor needs the weights in it to advance timing though. if the distributor don't have the weights in it to advance the timing, then you need to change it to a distributor that does for the engine to run right.
Accelerator pump in carb not working right. Look down the barrels of the carb, looks like a 2 barrel to where both barrels are running the engine. Tap the throttle just a little a couple of times and you should see the gas squirting in both barrels. If not then the accelerator pump is not working right and is leaning out the engine on acceleration.

Don't know the year of the motor, but the early to mid 80's engines, some of them used computer controlled carbs and distributors, if you got this setup, it would run way better with an older carb and distributor on it that don't need the computer.

You might be right on the vacuum leak! I sprayed some ether around the carb gasket and the engine jumped up in speed. I had these vacuum issue 2 years ago and I thought I fixed them, doh!

A ha!! that would do it, LOL. Awesome build by the way. Built my own too.

Tractor?? this thing a a freggin tank! it looks like a beast!

Union went on strike at the Iowa Tractor Factory due to unsuitable working conditions. Management and union leaders are trying to resolve facility issues.

Man dude!!! Talk about an indestructible tank! You need to make it street legal, lol!

Well I got the machine out to test the new gaskets and everything is sealed up after testing with ether.  Unfortunately the same issue is occurring. Stutter at acceleration and very poor response to loads.  I also lost the master cylinder to the clutch, I will swap over to a mechanical clutch linkage.

Overall though the chassis/track system performed very well in the snow.  Just need to get the engine and powertrain running right!

Man, that's gonna be so cool!!!! Can't wait for you to finish.

That is just so cool.

That's awesome man! I can only hope to do something of that sort one day myself

How does it ride, is it a rough ride? I noticed when I was driving mine, the ride was so smooth like riding on air, but I got the tandem axles on all 4 A-frames with air shocks. Just curious.

Oh, maybe take a look at the carb, to see if the accelerator pump is squirting in each barrel. Carb looks like a 2 barrel, right? or is it a 1 barrel with a vacuum operated secondary? Cause if it's the latter then it will squirt only in one barrel (the primary). If engine will speed up slow with no problem and not under load that is.

How's the vibrations with the engine mounted solid like that? Or is it mounted solid?

Watched the video's of this thing on youtube. It's pretty cool. Track system looks pretty bullet proof too, glad that it worked out good so far.

A fine winter romp from yesterday.


Notes for my sanity:
-Need cushioned front Walking beam stop ~4" travel due to crazy endos
-Steering brakes, way to allow fluid from master cylinder reservoir to accommodate pad wear
-3/8" rebar chevron grousers (cannot road these) or angle iron track extensions for winter.
-Foot throttle too sensitive, needs dampening/resistance for rough romping
-Look into high speed engine stuttering