Hi guys,

I have a question about the 4-mix engine created by that company that rhymes with 'Steel' in the States and 'Still' here in Aus (I don't want to bait the Search Engines by using the brand name on a motorcycle site).

I've seen guys trouble-shooting lawn mowers on here before so I am asking here out of desperation as there is not a great deal of info on this engine on the 'interwebs'.

The 4-Mix is a four stroke engine that runs on 2-stroke fuel.

It's an old powerhead I was given by a friend because he's given up on it. It's old but the piston and cylinder seem to be in good shape. It was revving high and I found an air leak in the gasket glue around the timing cover. I sealed it up properly and it ran beautifully! (It's a wonderfully torquey machine). Anyway, I used it for a while then it started to rev strange again. Adjusting the low and high idle screws worked - intermittently, then it developed a new symptom - It starts well but when it idles it seems to 'chug'. That is the head shakes back and forth in a relatively slow but chunky rhythm and it sounds deep. On the throttle, the chugging just gets worse and no power. Adjusting the screws would occasionally produce a sweet rev, but only for a few seconds. That no longer works.

1) I've cleaned out the muffler and cleaned the exhaust port (they were blacked up with dry soot but no where near blocked).
2) I've adjusted the valves to spec and replaced the valve cover gasket.
3) I've cleaned the carb and replaced the gaskets and diaphragm)
4) Swapped the spark plug (the plug looks good ... tan-ish colour)
5) I tested the coil on a multi-meter and got somewhere around 1470 (I can't find a spec for that).
6) New air filter installed

Has anyone here got experience with these engines?

Any advice on how to proceed would be greatly appreciated.

Cheers

justin_o_guy2 wrote on 06/21/20 at 02:51:48:



Hey JOG, Its a combi-tool head. One of those ones that you can switch the attachments on (brushcutter, hedger, pole-saw etc). I've looked at most of the videos I could find on YouTube. My thoughts were that it could be the timing but I also can't see how the timing would go out. When I had the cam cover off it all looked in pretty good shape too.

My second hunch was it could be a faulty coil. I'm trying to avoid throwing any more parts at it just yet so I'm trying to eliminate any other possibilities first. The fact that the carb adjustment screws were having an effect on the symptoms at one stage has me leaning in the direction of fuel supply. I'm not very experienced and the carb is an old model so it's a bit tricky finding info. Also the fuel lines run through some kind of grommet-like setup into the tank and it's not obvious to me how to get those out (without breaking something in the process).

I was hoping someone might recognise the symptoms and point me in the right direction before I start taking the whole thing apart. I don't mind doing that ... but a shortcut would be good  

LANCER wrote on 06/21/20 at 13:43:44:





Ya know, I never thought to remove those screws and inspect them when I cleaned the carb!!  

I'll give that a go.