[patoncastle]

Hi All,

I'm after some advice on a Merry Tiller Titan 5HP I got of Ebay for £100. It starts with a clean/new spark plug (which sparks well as told ignition bit was replaced) but after 5-10 mins use it dies on me and wont start.

The clear reason is the spark plug is all dirty (very sooted even with new plug) with black soot. My limited knowledge says that its running rich (to much fuel) but have adjusted the fuel/air mix and keeps doing this.

Its a fantastic bit of machinery and turns to soil very well. When it works.

Could there be more to it than just running rich? Anyone else had similar issues?

Many Thanks

[Kleftiwallah]

I tend to think it may be fuel starvation.  Is there a vent hole in the fuel cap?  This may be blocked causing a partian vacuum in the tank,  while you are pulling at the start cord, the vacuum may have time to dissipate and so the engine starts again.

Just a thought,   Cheers,    Tony.

[smud6ie]

After it stops can you restart it straight away by removing the the plug and replacing it with a clean one?
Make sure the choke is going all the way off.
Try   running it without the air filter and see if things improve,if they do,clean or replace it
Is it a Briggs engine with the carb fixed directly on top of the fuel tank?
smud6ie

[Bigbadfrankie]

Give it some redex

[patoncastle]

@Tony Thank you for the advice there is a little hole in the top of the filler cap. Ive never checked to see if its blocked. I didint realise the sooting could be fuel starvation.

@smud6ie It is the merry tiller titan with the carb on top of the fuel tank. I assume the choke is all the way off as its pushed in. Ive not tried putting new plug straight in after but believe it would start and run and do the same. I'll give it a go with the filter off (which does seem clean) to see if that makes a difference

@bigbadfrankie Thanks for the advice, ill give it a wee drop of redex next time.

If it helps is starts running (sounds like it could be running to fast) and as time goes on starts to hiccup here and there until it gets to much and it dies (smokes from the exhaust).

[Topscaff]

Probably the diaphram is gone in your carb they sometimes perish and leave a small hole in the rubber not visible to the eye, it's an easy fix if you know what you are doing, goggle it on youtube, Mike

[bluedog]

 :)hi just read your issues maybe a good clean out of the carb is needed, not to hard to do look on interweb thing and put your engine make in and someone somewhere will have a pdf file with lots of pic to show you how to do it, then start at base settings and ajust until it sounds right and works ok,some briggs and strat engines needed leaded fuel.
go on briggs site and that will give the age of the engine if its old put lead subs in petrol it may help or just tell it to get a grip or you will buy a new one this has worked in the past with a pear tree try it .
thanks
love peas and carrots to all

[patoncastle]

Probably the diaphram is gone in your carb they sometimes perish and leave a small hole in the rubber not visible to the eye, it's an easy fix if you know what you are doing, goggle it on youtube, Mike

What effect would this have if it was the case? Would that make the spark plug soot up and then stall?

[R Tallentire]

A perforated diaphragm allows the vacuum in the inlet tract to suck fuel though the hole, richening the mixture. This is normally accompanied by bad cold starting, unless the fuel tank is brim full, as fuel runs out of the pump chamber overnight (often onto the tank top) and the system takes several pulls to re-prime itself.

Once you have a good clean carb, the correct initial setting for the mixture screw is, screw in until it just bottoms in the jet, then out about 1.5 turns. Once warmed up set the revs to above half throttle and screw in slowly until the revs drop, then out, the revs should rise and then start to drop again, the correct setting is midway between but check that it runs cleanly at all rev settings and if rapidly opening the throttle causes the machine to stall, open the mixture screw slightly and check again.

[patoncastle]

Thank you for the above post that is most helpful. It does seem to suggest I need to replace the diaphragm and give the carb a clean up. A good winter job me thinks.