MZ Project Won't Start - now running

[stuart-glos]

The project MZ has always started very easily, from cold, warm or hot, but today it just wouldn't fire up. It's a 301 with an ETZ251 engine fitted.

Good spark at plug. But I cleaned it anyway. Then I changed the plug (just in case) but still no luck.

I cleaned out the carb - looked ok - fuel getting through - choke working - jets clear - but still no go.

Checked the air filter. Tried bump starting it - still nothing.

Drained the carb again & used fresh petrol - still zip.

The spark plug was wet with petrol and I am now stumped & rather hacked off.

The ignition is electronic, so should be ok. As I said, it's always started very easily......

Any ideas?

[DAVID THOMPSON]

try an other plug may have fowled that one out
dave

[radiograf]

Do you have the choke still open?
I usually find the best start procedure is as follows:
From cold
1, ignition off, petrol on, choke on.
2, kick over twice, to prime the engine.
3, choke off, ignition on, kick engine over.
Should usually start 1st or second kick.

[Windmill]

If it's very wet, Plug out, petrol off ,turn over a fair bit & leave to dry out with plug out. This time of year I'd suspect damp in electrics, check important connections and a bit of wd40 wouldn't go amiss. Good visible spark can fail under compression even though it looks ok, if plenty petrol getting through it's got to be electrics. Only proviso, make sure carb isn't flooding........

[stuart-glos]

I think it was a carb problem.

I had a spark previously (but used a new plug anyway) and replaced the spark plug cap with a known good one, too. But I spent an hour cleaning out the carb, blowing through the various air ways and jets and it started again quite easily.

I would have preferred to have found the actual problem but happy enough it's now running again.

Expecting problems I started it with the air box and rubber hose removed (so the carb had no filter at all) but it started and ran well (on it's stand). Does that mean the mixture is too rich?

I was thinking about getting rid of the air filter anyway and using a K&N type pod filter - would I need to change main jet in the carb? What do other people do or think about K&N pod filters on an MZ?

ta
stuart

[Skorpion]

Leave well alone you will cause more problems if you fit a pod filter, the MZ really needs the length of pipe that go's into the air box to run right, filter pods get wet/damp and restrict airflow. more trouble than they are worth.

[DAVID THOMPSON]

2 smokers are very fussy about intake and exhaust plumbing
leave it stock ...

my 4 stroke rt125 is tuned to about the max from the factory
most any thing you try just makes it go slower and use more gas

DAVE