mtx 125 issues oil/milky/rusty colour on spark plug

[joe.llewellyn]

right i bought a mtx125, dont know anything bout it couldnt tell you yr..

its a 2 stroke
its got a new spark plug
it has petrol in her
no on off/switch

right the problem is when i kick it she wont start so i take the spark plug out of her and it has some substance on it, the only way i can describe it is like a rusty petrol substance on the end which just wipes clean off with my jumper.... when i put the plug back in she kicks over and starts for 10 seconds.... i can repeat this but always same outcome except if i clean the spark plug and bump i manage to ride for bout 20 seconds, i suspect water in the engine so looked online couldn't really understand but one guy said look at the oil in the engine so i unscrewed that and its a pale milky shitty colour...... any suggestions Smile

[stickybackbob]

Could be a blown head gasket or been sat out in the rain. Drain and replace the oil, drain and replace the petrol, clean the carb bowl out and try again

[bladerunner]

Sounds like head gasket. Not a big job on a single cylinder 2 stroke but the MTX does not like being over heated as it warps the head.
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Current bikes...cbr929, KDX200's, Rd125lc mk2, RGV250's

[joe.llewellyn]

i do know that its been sat in the rain, iv already cleaned the carb but tried kicking it over aftyer this, should it need recleaning. and im not that good on this stuff, i know on 2t the oil you buy is 2t that gets mixed by that little lever and spring on the side of my engine, but what oil do i put into the engine i think its the transmission oil? am i making any bloody sense here?

[joe.llewellyn]

plus, will this be why my spark plug is getting a build op of rusty petrol like shit on it?

[stickybackbob]

From your description, there is water in the gearbox oil. Don't know the MTX engine but it's possible that the water pump seal could have gone allowing cooling water into the oil. Drain the old oil out via the sump plug on the bottom of the engine. Replace this with engine oil Castrol GTX, etc) If this goes milky again, then it's not rain water.

The rusty shit on your plug could be crap that has made it from the tank. Water will sit right at the bottom of the petrol tank with petrol floating above it. Drain the tank and put plenty of fresh fuel in. If this doesn't clear it, then it would suggest that the head gasket has gone or the water jacket is cracked somewhere.

Replacing a head gasket on a two stroke is very easy. Between 4 and 6 nuts to take off the head and then see if the gasket shows signs of blowing.

[joe.llewellyn]

thanks alot, changing the head gasket, im right in saying i undo the bolts holding the thing that houses my spark plug, and it will be the gasket that is between the thing i just undid and the rest off the engine...? and how much oil will i need to replace the oil?...is this the right stuff? https://direct.asda.com/Castrol-GTX-Engine-Oil-15W40---4L/001022022,default,pd.html?cm_mmc=ad-ppc-_-ggle-pla-_-Automotive-_-001022022&utm_source=ggle-pla&utm_medium=ppc&utm_term=001022022&utm_content=Automotive&utm_campaign=ad