Hello everybody, this is my very first post on the moped army but not my first visit. This is an excellent forum for those of us with little bundles of two stroke fun and has been of great benefit to me in accustomising myself to the inner workings of my newly acquired 1978 puch maxi "s".
However I still find myself at a loss as to why it refuses to run for more than ten minutes at a time!
This is the problem I have; after ten minutes of starting and running fine the motor starts to die refusing to pick the revs up and ultimately stalling.On removing the spark plug it is completely sooted up with heavy dry sooty carbon deposits.When I replace the plug with a new one it starts and runs fine for ten minutes again until the same thing happens.
The bike has no air filter so I would assume this would make it run leaner rather than richer but I will stand corrected if this is not the case.
I have changed the fuel, cleaned the carb,cleaned the petcock, changed the transmission fluid and removed and checked the piston and barrel. It still has the original barrel and piston after 5,000 miles and whilst there are some light wear marks on the barrel and some scortch marks on the piston they appear to be in reasonable condition. this is borne out by a compression reading of 180 p.s.i (cold) .
I have not checked the points, condensor or timing due to a lack of tools,expertise but as stated above it starts and runs fine for ten minutes.
It does not have the correct plug in at the moment but again Iam not sure which is the correct type for this model,I am also not sure what horsepower this model has, it is a 1978 U.K supplied single speed maxi "s" with a bing 1/14/152 carburettor.
In closing I appreciate that this is a long post asking multiple questions but I have every confidence in the members of this forum and in their ability and willingness to help.
If the combined efforts of those more informed than myself can get this charming little puch back on the road then you will have the eternal gratitude of both myself and my family and will have saved yet another automotive antiquity from the "parts for sale" section of ebay.
Many thanks and best regards,William Rafferty.