[johhnyscenic]

Hi There - new on here so Hi to everybody

I own two Merry Tillers(one Major 3 hp and one Titan 5 hp)

the Major will run(after fitting a new magnetron ignition coil but cuts out after approx 3 minutes) - would this be a possible diaphragm problem? - new spark plug fitted and air filter. would a poor worn rubber grommet on the breather pipe going from the carb to the engine block affect this?

the Merry Tiller Titan is another project for when I get the Major going!

Many Thanks.

[R Tallentire]

Doubtful that it is the diaphragm, this pumps the fuel from the tank into the weir chamber in the top of the tank. The weir chamber acts exactly like the float chamber in a normal carb except excess fuel spills over the weir and back into the tank, rather than flow being stopped by a float needle in a normal carb. Holed diaphragms usually make the engine bad to start, as fuel doesn't get lifted into the chamber too well, leading to a weak mixture exactly when you need a rich one for starting. It is worth checking diaphragm and cleaning the filter on the pick up pipe, also cleaning the main jet, hidden behind what looks like a nut round the mixture adjuster. It is also possible the adjuster has been set far too rich, check the spark plug nose colour, black and sooty indicates too rich a mixture.

[johhnyscenic]

Many Thanks to R Tallentire(Richard)? for his sound advice - will remove the carb and check these carb possible issues and replace the diaphragm(as a matter of course)
having explored this forum site further(wish I had found it years ago)! - I observed R Tallentire,s post of information regarding the kill switch(brass piece adjacent to a Tufnal piece) in which a picture was posted (without sounding disrespectful to anyone on this forum) - sometimes these pictures are hard to view/follow - so this prompted me to view YouTube and I found videos(in 4K quality)(Machinery Restorer)"Rusty engine Rebuild Restoration - will it ever run")? -of a Briggs and Stratton engine - which(to a layman like me) - makes things easier to understand.

will let you know the progress I have made(eventually)

Kind Regards to All.

[johhnyscenic]

Hi All

just removed petrol tank and carb from the Merry Tiller Major 3HP - pick up pipe(long brass pipe) completely blocked(soaking it in white spirits at mo)(filter end) - poked welding rod(minus flux) through pipe.
inside of petrol tank Very Rusty indeed!

would anyone of you kind people  know A/ how to cure this - or B/ -  could you recommend a repairer - not sure if you can still buy these petrol tanks

Many Thanks

[JGM]

For a rusty petrol tank...
Remove it from the machine and take off everything attached.

• Wash it out with plenty of detergent and hot water. This gets rid of any remaining fuel 'gunge'
• Put a large handful of different sized nuts, bolts and washers into the tank. Nothing sharp like screws or nails.
• Put a cup of hot soapy water in the tank. Usually your tank cap will have a seal/breather holes in it, so you don't want to put it back on the tank for the next step. You can use the top off a 5l plastic container (like the kind used for screen wash or oil), you might need to pad out the thread with a few wraps of cling film to get a tight fit.
• Shake it, Shake it Shake it! Try and get the nuts etc. to rub against all of the inside of the tank at some stage.You could be doing this for 5 mins or 15 mins depending on the state of the rust. You may need to cover holes in the tank with fingers or your hand as you shake.
• Wash it out with plenty of detergent and hot water (saving the nuts etc.)
• Examine the inside of the tank with a torch. You may need to repeat the treatment while tilting the tank to treat a particular area. *Now is the time to fill it with water to check for leaks*
• Force dry the inside of the tank with a hair dryer to prevent flash rust.
  
• If I'm not putting it back together straight away I might shake a small amount of petrol/engine oil mix (or fresh 2 stroke fuel) around in the tank just to coat the inside, pour it away and leave to air.

[JGM]

For running then stopping...

First thing to check is something getting hot and then failing or a vacuum forming in the petrol tank.

Vacuum in the tank is caused by the petrol cap breather holes being blocked. Unscrew the petrol cap until it's still attached but loose. Start and run the machine. If it doesn't stop, that was your problem. Clean/exchange the petrol cap.

If it stops when hot, put a spark plug tester (between H/T and earth - not the spark plug) on it, and try to start (when still hot). No spark means coil/condenser faulty. If you have a spark, spark plug maybe faulty. Replace spark plug (correctly gapped) and see if that cures it. If not, you probably have a fuel delivery/valves sticking problem. Make sure you have fresh and sufficient oil to ensure the valves are lubricated.

With regard to the leaky breather tube, that shouldn't stop your engine. The pressure inside the crankcase pulses in time to the rise and fall of the piston. The breather just stops pressure building up inside the crankcase and causing problems.