Tecumseh OHH65 cuts out over bumps

[NightHawkJ30]

On my Manco 415-311D gokart on the engine the ground from the steering goes to terminal blade on the engine and next to it is Throttle cable. I remember seeing it like that so close and wondered hmm. So i started the engine and grabbed the cable end and touch it to the terminal

 

[Gasteffens]

Actually you know what it could be a ground

Next time I’ll try disconnecting the remote switch at the engine since it runs all over the place under the kart

 

[NightHawkJ30]

So its possible it if touches just a bit it give the symptom you describe.

 

[NightHawkJ30]

I stalled the engine out like that so i just carefully bent the cable end just enough from the engine terminal. Think later down the road ill put a piece of heat shrink tubing over the cable end.

 

[NightHawkJ30]

it used to be closer to then that but since i bent the cable end just enough to clear it.

 

[Gasteffens]

it used to be closer to then that but since i bent the cable end just enough to clear it.

I went out and looked and mine does not have that wire over there. Unfortunately it is too dark to get a good picture of the actual wiring arrangement on mine but I will try to get one soon of all the connections I can see. What I can describe that I see easily at first glance is a two wire (black/green) plug dangling in the air, and then another black wire that goes from the engine (can't say where at this time) all the way to the front kill switch. It takes a lot of turns and loop-de-loops and there are many metal clips holding it on along the way, so when I get a chance I'll disconnect that one near the engine and see if it makes a difference. I have lots of new wire from other projects so if thats bad I can re-run it but this time in a loom too.

Also it looks like there could be a lot learned by removing the fuel tank and seeing what's under there, so that's on the list to do soon too.

I was tinkering with this in tandem with painting some new parts I got from BMI, plus visiting with my dad while the rest of my family helped look after our kids... so I'll have to wait till I finish painting before I get back to the engine. I'm about done spending money on this engine, and so hopefully I can find some kind of smoking gun otherwise I'll just use it as it is until we get something else for it. I'm certain if the engine was put on a say a pressure washer or something stationary, it would run like a top. No noises, no smoke, doesn't seem to use oil and pulls hard when it's not stumbling.

Truthfully, I'm not heart broken to get something else, as I'd like to get a 6-7 hp engine with electric start and a small alternator to charge a battery and run a few lights, so we'll see when it comes time to replace the rear swing arm if I put this engine back on or not.

 

[NightHawkJ30]

Well if you ever don’t want that Tecumseh engine ill buy it off ya if you don’t want it.

 

[Gasteffens]

Well if you ever don’t want that Tecumseh engine ill buy it off ya if you don’t want it.

Ha, good to know! I haven't thrown in the towel just yet. I know they aren't the best engines in the world but I remember a lot of bikes/karts from years go that had them and they ran pretty good and have, at least to my ear, a decent stock sound to them.

 

[NightHawkJ30]

After having my Tecumseh 5hp Powersport since 1998. I think it a great engine to put on a gokart. In my opinion I thought they did pretty good.

 

[Gasteffens]

After having my Tecumseh 5hp Powersport since 1998. I think it a great engine to put on a gokart. In my opinion I thought they did pretty good.

I agree. Yours looks a little cleaner than mine. Do you know what was different between the 5.0, 5.5, 6.0 and 6.5 hp versions? The one I had on my old Manco (Dingo-Rattler) was a 6.0 with a primer, and this Yerf Dog has a 6.5 with a choke. Not sure if that makes a difference either. Here's the best pic from I have right now the same angle as yours there.

 

[NightHawkJ30]

Far as i know only horse power and torque was different like 5.0Hp was 172cc and 5.5 6 hp versions i think where 196 cc. All 5hp models had Primer and other like the 6.5 had Choke. But actually it depended on what the gokart manufacturer Wanted for there Gokarts or Minibikes.

 

[NightHawkJ30]

And oh yeah Tecumseh 6.5Hp is nice engine that with Torque convertor you be getting 35 plus.

 

[Gasteffens]

And oh yeah Tecumseh 6.5Hp is nice engine that with Torque convertor you be getting 35 plus.

Oh, I didn't know they have different displacement blocks - that would make sense. So the 6.5 is a 196? And then it sounds like the engines as they came down the line were somewhat "modular" depending where they were going, including non gokart usees.

I have a speedometer app on my phone and I have hit 24 with it so far, lol. I'm sure the torque converter setup has seen better days among other things. Plus after putting the new brake band on I have it backed all the way out and still may be a scosche too tight, which I believe is the swing arm is a little messed up there hence I have a replacement.

 

[NightHawkJ30]

Yes on the Serial number Tag it says Displacement 172cc i was surprised to see it. And yeah i would modular

 

[NightHawkJ30]

Yeah if service that Torque convertor you get that karts performance back to where it was when it was new. I always wanted Manco Dingo along with My Manco Terminator

 

[Gasteffens]

Yeah if service that Torque convertor you get that karts performance back to where it was when it was new. I always wanted Manco Dingo along with My Manco Terminator

When I take the engine off to replace the arm, I will do my best to go through the TAV system. Allegedly the previous owner replaced the driver pulley and belt, and the driver pulley does look cleaner than the driven, but the belt also looks like it has a tad much slop in it even thought the part number is correct, so it could possibly be a cheap one that is worn out already. If anything looks off I'll see about replacing some parts there too. But since I'm going to have it off this winter when we can't ride anyway, I may as well go through it all.

 

[NightHawkJ30]

Comet made those its good setup

 

[Gasteffens]

Comet made those its good setup

I’ve always been impressed with them over a standard clutch

 

[NightHawkJ30]

Yeah my kart has the comet 400 series clutch it alright but ill take a Torque convertor gokart any day.

 

[Gasteffens]

Yeah my kart has the comet 400 series clutch it alright but ill take a Torque convertor gokart any day.

Disconnected the kill wire at the little screw on the fan shroud. No change. Took it down the street and hit 31mph, not too bad ha. Honestly don’t want more than that for this machine.

Did a whiz bang job of moving the fuel tank, and the green wire looks like it rubs real consistently on the fuel tank bracket. The white part was rubbed completely through but I did not see any of the green gone, but it doesn’t mean it’s good either. Next I want to take the fan shroud and inspect all the wires in there for anything suspect.

This breather fitting where it goes into the rocker cover is loose - is there supposed to be an o ring or grommet there ?


Also putting more pics in the build thread.