What's on your bench today?

[Matthew Arnold]

If a carb freely lets out fuel then it is the needle valve that is either being held open or simply leaking allowing fuel to flow in to the metering part of the carb and flood in to the carb throat through the low speed injectors.

 

If you mean the engine becomes flooded because it won't fire and pulling over the engine on full choke fills the thing with fuel then that is different.

 

Assuming the latter if it has had a new carb on it - if it won't fire on say five pulls on full choke, have you tried holding the throttle fully open with the choke off and pulling the engine over - your problem may be that the fast idle mechanism that holds the throttle open isn't holding the throttle valve open as it should.

 

A blocked exhaust/spark arrestor will cause problems and worth pulling the exhaust off for a closer look.

 

It could be that the carb needs a better tune or that the engine is lacking compression enough to cause issues.

 

The other thing I have found with these four mix engines is that the valve clearence needs to be set 100% otherwise it causes all sorts of issues and this is also worth a look at.

 

I do specialise on two strokes and try to avoid the four mix engines - funny as I spent my youth on four stroke bikes and never had a two stroker:lol:

 

Someone else may have greater experience on your long reach.

 

Oh - it may have an auto decompressor mechanism that has jammed on... or off!

 

Cheers Spud will have a good strip down to have a look see but sounds like it is will out of my league of mechanical expertise so off to the dealers it goes unless it is a simple fix like a clogged air filter/fuel filter or coked up exhaust.

[Rich2484]

Cheers Spud will have a good strip down to have a look see but sounds like it is will out of my league of mechanical expertise so off to the dealers it goes unless it is a simple fix like a clogged air filter/fuel filter or coked up exhaust.

 

I have slowly given up on the four mix engines. Worst design ever. Better of with a good two stroke.

 

Still have one on bits that I just can't get to the bottom of. The only good thing about them is they have more torque than a two stroke, so are perfect for long reach pole saws. And big strimmers.

 

My advice is save yourself some aggro and get a big two stroke on the pole.

[GardenKit]

You just can't beat a good 2 stroke.

[Rich2484]

Someone was asking about clam shell engines a short while ago.

 

Below is an ms170, good example. The whole engine comes out in one only held by four screws that are on the underneath of the saw.

 

So a "normal" type engine will come out with the bottom part of the crank case being part of the saw case.

[mikerecike]

Someone was asking about clam shell engines a short while ago.

 

Below is an ms170, good example. The whole engine comes out in one only held by four screws that are on the underneath of the saw.

 

So a "normal" type engine will come out with the bottom part of the crank case being part of the saw case.

 

 

that was me - cheers rich

[Rich2484]

Busy busy busy....

 

Ms170 done. Mantis rotovator done. Two electric chainsaws done. One husky cut off saw done. Other one in bits for spares.

 

Two strimmers done. Barrie, that gearbox had a small thread on it. He a panic moment when I fitted it, but found some that where the right size.

 

Now its the crushed 200t to look at, and a makita cut off saw that needs new piston and pot.

[Eddy_t]

Cylinder fitted and all connected, now I need to advance the timing

 

 

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[Rich2484]

Started on the ms200t (humpty dumpty)

 

Stripped her down a bit and started the rebuild service. Re drilled and tapped the holes for the fuel tank housing as the old bolts wouldn't go tight. To re tapped for the m8 bolts instead.

 

Recoil started but needs new spring as the old one was lost. Also needing a new exhaust, these as far is I can tell are the only needed parts as the rest are there.

 

A good note to others, never leave a saw where it could get run over.......

[spudulike]

Been porting a 371XP tonight, the top image is before, the lower - after.

The exhaust port has been widened as has the inlet though less so. The lower transfers have been modified heavily and the rear transfer has been re-modeled to improve scavanging.

[Rich2484]

Been porting a 371XP tonight, the top image is before, the lower - after.

The exhaust port has been widened as has the inlet though less so. The lower transfers have been modified heavily and the rear transfer has been re-modeled to improve scavanging.

 

Someones got some fancy new photo software, :lol::lol: