Briggs and Stratton carburettor

[Ed_Dinning]

Hi Gents, has anyone got a Pulsajet carb as fitted to Briggs and Stratton 3.5 or 5HP vertical shaft engines, or a scrap engine so that I can repair mine?

Thanks, Ed

[singlepentode69]

Sorry ed I boned one last week have you tried your local tip I used to get mowers from tips a few years ago as lots get binned this time of year mainly because the owner has left old fuel in.
Regards
Robin
P.s I will have a look at my allotment tommorow as the have a scrap heap there

[singlepentode69]

I had a look today none on the scrap heap at the allotment I will keep an eye out invade any come up in the near future as it's always worth having a spare in stock .I did get two strimmer a to play with later on.
Regards
Robin

[Ed_Dinning]

Thanks Robin. It is a big beast of a mower, probably from the 40's, but does a good job on the rough grass at the back.

Ed

I had a look today none on the scrap heap at the allotment I will keep an eye out invade any come up in the near future as it's always worth having a spare in stock .I did get two strimmer a to play with later on.
Regards
Robin

[singlepentode69]

Maybe worth a look at your local tip.what make is it a rotary I presume I had a collection of tacos and ransomes mowers with a varied selection of engines from villiers to Briggs They do have a super cut .sometimes the local garden machinery people have them in the scrap pile as part of a trade in deal.
Regards
Robin

[Ed_Dinning]

Hi Robin, local tip now run by the council and nothing to be removed!!, hence useless.

It is a 5HP 2500 RPM vertical shaft 4 stroke, so has a horizontal carb barrel. It looks slightly military in faded olive drab and drives a large disc with triangular cutters fitted to it through a right angle gearbox. It uses a poly-vee belt with tensioner to drive the rear wheels.
Slug of fuel will get it going but it takes turns in either running for a short time (not lifting fuel from the "cup" in the fuel tank) or running for 5 mins (not replenishing said cup with the "Pulsa-jet).
New jets and diaphragm, ultrasonic clean and blasted with compressed air all to no avail.

Ed

Maybe worth a look at your local tip.what make is it a rotary I presume I had a collection of tacos and ransomes mowers with a varied selection of engines from villiers to Briggs They do have a super cut .sometimes the local garden machinery people have them in the scrap pile as part of a trade in deal.
Regards
Robin

[singlepentode69]

I see the filter in the fuel tank is not blocked is it they sometimes have a wire mesh filter inside the tank sometimes fitted to the tap.The other things that stop the fuel getting to the carb is a small hole in the fuel pipe which seems normal when removed from the carb ie fuel goes through but when the pipe is fitted back on the hole sucks air in and causes an airlock I had this on a ransomes you could hardly see the hole.
Regards
Robin

[Ed_Dinning]

Hi Robin, filters look OK on both pipes, but a hole in one of them is a possibility.
One thing seen on this carb is a hole fron the top to the base flange that goes onto the tank. This is blocked from the top with a brass pin that is a push fit at the yop, but has a good 1mm clearance on the tank flange end, no sign of internal drillings into this hole though./

Ed

I see the filter in the fuel tank is not blocked is it they sometimes have a wire mesh filter inside the tank sometimes fitted to the tap.The other things that stop the fuel getting to the carb is a small hole in the fuel pipe which seems normal when removed from the carb ie fuel goes through but when the pipe is fitted back on the hole sucks air in and causes an airlock I had this on a ransomes you could hardly see the hole.
Regards
Robin

[singlepentode69]

I think they use the same castings for most of there castings and fill up any unused ones or blank of when casting they used to do that on the zenith carb fitted to suffolk colts and punches too.
Regards
Robin

[Nick]

Not sure if it will help - I had a problem last year with my Honda mower which required a carb strip & rebuild - I used much the same techniques as you - strip, ultrasound, STP Carb Cleaner (wonderful stuff), replacement gaskets etc. However, the varnishes in the fuel had also 90% blocked the in-line fuel filter - it *looked* fine, even seemed to pass fuel, but was sufficiently blocked to render it useless when the engine was running - see below - cut open, it looks like its just got the usual crud (bits of grass etc.) but what you can't see is the varnish blocking the pores... the give-away was that blowing through it was a real effort - the whole fuel path needs to be free-flowing... (check the tap too...).

Replaced the filter and engine was *much* happier