OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions on Other Engines Yamaha SHOGUN 2 stroke

Hello all
I am after some thoughts on this engine, that I have never touched before.
After pulling it apart to clean it, I am noticing a quality built engine.


Here are some markings.





The main things I am unsure of:
1. is the small flywheel
2. oil fill plug on the back of the engine (is this for a gearing?)
3. 106cm cubed (I would expect to see a larger sized engine on a 21 inch base)

The sticker mentions reduction gear & direct drive, which I am also unsure about.




There rings are loose in their grooves compared to other 2 strokes.


Head gasket looks to aluminium.
Exhaust has a removable plate for cleaning out carbon.
Exhaust gasket is a non ferrous metal looks like brass.



The piston and bore is not damaged and is making the right sucking noises when turning it over.
I haven't split the case.
Will clean the carb tomorrow and put it together for a test run.
Cheers from Mark

We have one previous thread on that engine Mark:
https://www.outdoorking-forum.com.au/forum/u...p;Words=yamaha&Search=true#Post11309

It does answer one of your questions: it seems the engine has a specific oil reservoir for the bottom crankshaft bearing.

I don't think anyone would make an engine that had a brass gasket in contact with an aluminium engine: the galvanic cell thus created would result in corrosion at awesome speed, with the aluminium part being the sacrificial anode. Most likely it is some kind of coloured anodized finish on an aluminium part.

Thanks Grumpy I read that thread.

Found out that engine has 3 main bearings.


Came across a fault today doing the carb, see image of broken fuel bowl pivot & my repair.



Still haven't found a repair manual or exploded diagram.

Found with a bit of searching, that a lot of these engines are in south Africa.
The 3 wheeled commercial mower is interesting.



Some features.

The carburetor repair should be OK Mark, provided you got it square, and the screw doesn't come loose (I'd have used loctite on the screw, and probably let it sit around for a few days before exposing it to petrol - loctite works by corroding the metals of the two parts so they are chemically bonded, but it takes time to work unless you clean both parts extremely effectively with industrial solvents).

At 14.8 kg I think that 106 cc 2 stroke weighs as much as a Briggs of the same output, so it isn't a lightweight engine. However the base engine is probably quite a bit more durable than an aluminium-bore Briggs too. Depending on whether they used another Mikuni carburetor and a complicated off-beat linkage like on the Suzuki M120 engine, it might have been quite a good choice for a contractor. However I think for most contractors, durability is less of an issue than reliability and low service costs. Fuel consumption also matters, and I doubt it performed very well in that regard.

I like the carby fix, I will use that idea in the future. I have a genuine yamaha carby for a pw80 that I will try it on. Cheers.

I have 2 of theses engines, on Greenfield bases. Fantastic engines,
I recently bought 2 carbys for them (Ebay, came from Thailand)
[color:#FF0000][size:14pt]MT110 Carby ebay link[/size][/color]

they do the techumseh carbs too and quiet a few others , ordered one 3 weeks ago , still not here

I ordered 2 tecumseh carbs from a mob in China from ebay a month ago. Got them last week. 3 or 4 week wait unfortunately is the norm for these carbs. cheap price I guess theyre not in a hurry to send them out.

I also have the same mower but it's labelled "Blue thunder" not "Shogun". A brilliant little engine VERY torquey. cuts through anything. When I got it it wasn't running. Change the air filter and clean the carby out and vroooom! I'm torn now though - I love using it on long grass but to let my grass grow long enough to have fun in I have to stop playing with other toys!

Pete

I had 2 orders, the 2 carbys from Thailand & 3 carby kits from west Melbourne..

I'm in s/east Melbourne.. 2 carbys 8 days / 3 carby kits 16 days.
all good products though.