Honda 4 Stroke

[RickH]

Have a Mantis Tiller … (lightweight rotovator)
Great bit of kit for creating fine tilth when incorporating compost etc. into Veg beds.

It’s only an occasional use machine, after use I empty fuel and run carb until empty.
The issue is each use it starts very easily….and idles happily, but when you operate throttle and clutch brings in tines, it revs up, then bogs down, if I don’t leave throttle go it will stall, it acts like this for at least 10 mins, then clears and runs OK.

I can leave it idle for 15 mins, to warm up,… but makes no difference.

I stripped carb, fitted new jets, gasket, fuel, pick up filter and fully cleaned … was OK for one session, then back to same issue.

I only use E5 petrol, have cleaned filter. Strange that it runs OK after 15 mins of bogging down.

 

[Burnerman]

Have you tried just giving it a little bit of choke, just to see if it prevents the engine failing?
These things run chronically weak which is why it can behave when fully hot - generally with some power reduction though.
John

 

[RickH]

I’ll try that suggestion.
On my bench tonight, oil change, grease gearbox, cleaned air filter and spark arester.

 

[Burnerman]

I guess you have the GX25 engine, with the Walbro carburettor, primer bulb on the bottom?
Ideally the rubber diaphragms need replacing too, but often enough a replacement carb from Amazon or whatever is the cheaper option.
John

 

[RickH]

It is the GX25 engine, No the carburettor has priming bulb on the right side, but I don't know the make of it.
Bulb is as picture in manual ....

 

[Burnerman]

It does look like a Walbro derivative - there are so many!
Just one point......the plastic quadrant that is turned when you squeeze the throttle - that actually lifts a needle out of the jet a fraction, and sometimes it can be adjusted by a tiny allen key on the top. Anticlockwise to richen, but adjustment isn't usually recommended.
It's probably still worth looking out for a replacement carb though - they are really good value and I've had very few duds.
John

 

[mrrusty]

For the small amount you use it's worth always using alkylate fuel in garden machinery - no need to drain - it doesn't go off https://aspenfuel.co.uk/

 

[RickH]

Thanks .. but I have E5 to hand so I use that .... it's no hardship tilting machine to empty tank, and then run to dry.

I have no issue with starting, which is what you would get with stale fuel.

 

[mrrusty]

It's not just the starting - Ethanol in E5 and E10 has a habit of degrading some materials, and the absence of it in alkylate fuels removes this problem.

 

[Burnerman]

I can fully second that one......although some machinery- especially the expensive makes - can handle E10, many certainly can not.
I'm finding many problems with fuel pipes, diaphragms, petrol taps and filters degrading very quickly indeed.
John