OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Walk Behind Lawn Mower Frames Reel Lawn Mowers, Atco & Villiers etc. Scott Bonnar 45 Randomly Stalls

Just a question with assembling the diaphram, apart from lining it up 100% and screwing it diagonally is there anything else i should be aware of? Its still struggling to start and think it is something with the diaphram... the spring sits correct to me.

Hi Mb,

You can't do any better than how you've described it.

I'm just wondering if you've blown out all the various holes and the supply tubes back and forth to ensure ease of fuel passage.

I'm only saying this because when I do any carburettor work you won't see any grass stuff floating around the place. I will always practice being Dr Shaun Murphy (The Good Doctor) when doing any carby work.

Cheers,
BB.

just a question as still having an issue with starting, would the mower continue running if there was a blockage in the carby still or issue with the diaphragm? It seems to be an issue with starting it if left for over a day or so... it still seems to me it would be from the diaphragm to pump the initial fuel into it???

Hi Miloboy

Looks the same model as my friend over the road has and he was having trouble starting from cold. What I found was when the throttle lever was set in the start position the cable wasn't traveling far enough to activate the choke butterfly. I adjusted the cable and his starts fine now, maybe worth a look at. Of course this only effects a cold start. The screen on the end of the fuel pick up needs to be very clean also.

Cheers
wce

That's a valid point about the choking method.

Is yours a chok-o-matic which in other words it pulls the choking mechanism out when the cable is pushed fully forward ?

Yes when the lever is in the choke position, the choke butterfly is closed all the way. It opens up completely when the lever is adusted to full revs.

For a cold start, when pulling the cord, does the diaphram acts as a pump to draw fuel up into the carby and into the combustion chamber?? Its like there is no pumping effect to get that initial spray of fuel on a cold start....

Hi Mb,

So if you leave the the air cleaner off and tip a small amount of fuel down the throat does it start well and then continue running ok or does it soon after falter and stall ?

Cheers,
BB.

Some years ago I looked at trying to fit a primer bulb from a whipper snipper to these because they usually only need a sniff of fuel to get them to fire, but then it all got too hard and I gave up

Hi Norm,

Yes the later Briggs had one fitted on the vertical shaft engines and that helped them immensely, why they never did it on the horizontal shaft engines I don't know.

Cheers,
BB.

Yes if i tip some fuel down the carby inlet (where the air filter is) it fires after 2 or 3 pulls of the cord. From then it runs fine and now doesnt stall. Thats the only way i can mow at the moment otherwise i would be pulling the cord until sunset...

And that is probably what you will have to accept, motor is probably a bit tired and not creating enough suction to draw the fuel up on start up. This is why the primer setup was so much better

Fair enough. I am half thinking of an engine replacement down the track, does anyone know what make is best for a replacement? I found a briggs that will swap straight over but is it worth going to a honda?

Hi Mb,

I guess it's up to you on that one, it all depends on how much you want to spend. There are plenty of Chonda's available for around $130~140 on eBay delivered so that's a pretty good option. Only thing is you'll have to change your clutch body to a 19mm unit as the 3HP Briggs you've got has a 5/8 shaft along with it's clutch half.

There are new Briggs slopers around and as you have the model with the lower kinked handle bars you can fit one of those straight onto the chassis, but those again are generally a 3/4 (19mm) shaft and will require the new clutch body.

Honda in my opinion are just way too costly and if you buy a Chonda and do regular oil changes etc. there's good life to be had out of one of those.

It's your call I guess.

Cheers,
BB.

Thanks very much for the advise BB. I have found a 2.5hp briggs for around $280 that apparently will fit straight on. It comes with 2 options on shaft sizes. See how i go. Cheers

Sorry it is 3.5hp not 2.5

Hi Mb,

Around that figure sounds about correct as the Briggs engines are somewhat more expensive than the Chonda's, but in saying that they are no better in my view and still idle quite roughly which is not what you want sitting on a twin rail model 45 that suffers from rail fatigue rather badly if not kept in check.

Cheers,
BB.

stupid question.... i have never heard of chondas before and I can't seem to locate any on ebay...
Any links?

Chinese Honda copies we just call them Chondas. Just ebay horizontal shaft motors and you will find heaps of them

that's what i thought... thanks