Briggs and Stratton I/C Alcon pump.

Now I know this not the exciting engine we like to talk about but, I am looking for some help, as in the title this engine and pump set up is a great set up, but boy the plug gets sooted bad and quick (sometimes but most times) I am going to try and get this running a bit sweeter, although it runs okay just a bit smokey as the exhaust side of the pump (cleaned before the photo) gets covered in soot, I read in the manual I found tonight about de-carbonising the engine, is it common to whip the heads of these engines? do I need a new head gasket to make a proper job of it, the carburettor set up on these like most small engines is a nest of linkages and springs, I have had it all off before when I thought the pick up was blocked, but its fiddley to work with, it puts me of getting in about it to be honest.

Most other engines I have had of this size just keep on running, with a few knowledgeable folk on here I thought I'd ask the question.

pics of engine.

Untitled by chrismac2012, on Flickr

Untitled by chrismac2012, on Flickr

Untitled by chrismac2012, on Flickr

Thanks Chris

Find a plug that runs hotter to burn the crud off .

Maryalice

Ah yes, after digging into the plug that is fitted, its no where near hot enough, an Oregon 77-324-1 (champion RCJ8Y) which is 8 on the heat chart, where the correct plug champion RJ19LM is a good bit hotter, hopefully an easy fix, thanks Maryalice for pointing this out.

I'll keep the Oregon one for my chainsaw, looks like it will be more suited to it.

Chris

Hello mate , most of you out there already know this , but the Briggs & Stratton engine needs to be set to tick over at quite a high 1750 R.P.M. , or fuelling issues start to crop up , basically these American engines are great , once set right , they can have essentially quite simple vacuum pumps built into the carburettors , that look horrifyingly complex , but hold your hand , they,re not . The pump lifts the fuel up out of the tank by using the engine,s vacuum pulses , then the excess not needed by the engine simply spills back down into the tank again , usually from the edge of a little cup formed in the tank top , the carb draws off from that cup the fuel it actually wants to keep the engine going , this is cleverly done with one simple thin diaphragm , that looks like a thin carefully stamped out bit of rubber sheet . it,s not rubber , so only use B&S own replacement part for this . The high tickover is needed ,, amongst other things like overcoming the easy - spin starting , to keep the pump working . I,ve worked extensively on one of these "dark red series " engines , & it had big problems , mainly coming from the exhaust valve being ran far too long with no gap , but I eventually beat it . Your pump looks like it,s been re-engined with this B&S , nothing wrong with that , but I suggest you test the compression pressure in the cylinder , as it,s possible someone used a 1/2 worn out engine to start with , you do this on a B&S by spinning the flywheel BACKWARDS , as this will over-ride the easy spin profile on the camshaft & reveal true cylinder pressure ( with the H.T. lead off ) . Try it without pouring a little clean sump oil down the spark plug hole first , note the pressure , then do it again after pouring some oil in , if there,s a noticeable difference , & little oil emerges out of either or both the induction & exhaust ports , then this indicates cylinder , rings & piston wear. Hence the black smoke.
Please keep us all posted , we,d like to know what happens .