Oil for Tecumseh 2.5HP

[Pyrotechnic]

I have an old Tecumseh 2.5HP motor that's going on a motorized bike I'm building for short distance commuting to help save on gas. During the summer it'll get started in the cool of the morning, probably around 70 degrees but the motor is going to also be working hard in 100+ degree heat. During the winter it will get at lowest around 35-40 degrees.

My initial thought is to run Rotella SAE30 in the summer and 15W-40 in the winter.

Reading through the threads here, some people run Rotella T6 5W-40 full synthetic just because the amount of oil that is required is so small so cost is not an issue. Since it's synthetic, the high heat of an air cooled engine and oil breakdown is not an issue?

What route would you guys recommend? I know I probably cant go wrong running SAE30 for the summer, it's more cold start protection in the winter I'm not too sure about. Is the full synthetic route going to be worthwhile or I should I just stick to the cheap and proven dino oil?

 

[troyb43]

If the engine is not using any oil now, try some Amsoil ASE. It's a reasonably priced SAE 30 synthetic that is also rated at 10W-30.

 

[eljefino]

The 30 weight will do you well. Remember the engine has a fan for stationary apps but you'll be subjecting it to airflow from the bike moving.

Have fun, my 2-stroke motorized bike doesn't leave me in this quandary.

 

[meep]

I think any stout oil would do. Wouldn't worry s much about a straight-weight. Agree with above-- if it doesn't leak/burn it, go ahead and use a decent synthetic or rotella/hdeo.

Are you running the throttle to the speed regulator or actually to the throttle on the carb? Tec engines in go-kart service run to the regulator assy and get thrown rods. I'd think you'd want to mod the throttle linkage so you have direct control, OR modify your driving habits so that any roll-on didn't always mean WOT.

M

 

[Chris B.]

German Castrol?

 

[greenaccord02]

Your plan will work fine. In fact, you could just as well run the 15W-40 all the time.

 

[Pyrotechnic]

Thanks for all the oil advice. I don't know yet if it uses any oil yet since I haven't run the engine much more than a minute or two.

Originally Posted By: meep


Are you running the throttle to the speed regulator or actually to the throttle on the carb? Tec engines in go-kart service run to the regulator assy and get thrown rods. I'd think you'd want to mod the throttle linkage so you have direct control, OR modify your driving habits so that any roll-on didn't always mean WOT.

M


Right now I have it set up so the governor will still function. Let me try to describe it the best I can.

Between the governor arm and the throttle butterfly, there is a solid link rod.

Now between the governor arm and the small lever that the main control level pushes on, there is a small spring. I have my cable hooked to that small lever.

Is this how it should be? I haven't really tried it out yet. It seems like a little bit of cable pull does get it to WOT pretty quickly though. This bike is going to have a belt and tensioner style clutch setup, so I am going to need some decent control as I'm not going to want to do a hard high RPM clutch dump launch every time I take off.

 

[greenaccord02]

That's how they should be hooked up, yes.

 

[eljefino]

I'm not sure a vehicle should be governed. That's more for snow blowers, rototillers, lawnmowers that hit a patch of thick stuff and need more power.

It's nice to have "cruise control" but you should gear the thing so wind resistance is at about engine redline. At redline you should let off the gas anyway.

Governors are just another thing to bog. Get a nice centrifugal clutch and hook the throttle control right up to the, well, throttle plate.

Free plug for Pablo's http://www.sickbikeparts.com

 

[steve20]

if you run it full throttle without the governor, eventually you'll blow it-may take several months, but it will happen