Saving Old Seagulls

Hi,
I have recently bought a 40 Plus with Amal Carb which is reluctant to start but which does eventually. The first few times I used it it ran well but one day I was caught in a bit of a squall and having run successfully for several minutes the engine note suddenly changed for a couple of seconds(higher revs) before it died. My assumption was a loss of spark due to water ingress in the plug cap. I dried all this out etc. Now it will start although still relucatantly (perhaps it is sitting too far down in the water) then as before it changes engine note - revving higher (and more freely ?) before dying and then cannot be started again. Can ayone help?

two stroke motors will have an rpm increase when the fuel/air mixture "leans out". look for an air leak or anything that would reduce fuel flow to the carb. both conditions woud result in a leaner mixture. a couple things i would look for is a loose carb(allowing more air in) or a blocked fuel filter or fuel tap (restricting fuel flow).

more experienced seagullers will no doubt have more specific tips..

I second the motion by Jerry that suggests inadequate fuel flow as a strong probability. That the engine runs well for a bit before revving up says that the carb is adjusted OK, and a wet or poorly-conducting HT wire (or bad plug) will show up as a series of misfires or as simply a full engine stoppage.

The reluctance to re-start right after it conks out is explained by the lean fuel condition right at that time. If you were to apply the choke as it begins to bog down & it runs better again at least for a bit, it's definitely a fuel delivery issue.

One might begin by removing the float bowl and turning on the fuel. The bottom of the exposed carb body should become somewhat incontinent and not present as a mere drip that would eventually fill up the bowl in the time it takes to play with another suspected part of the engine.

All of the usual suspects can be questioned at this point - the screen inside the tank atop the fuel tap, any type of screen if yours has one (as I'm not familiar with the Amal carb) and even the bend in the fuel hose, where sediment could pile up over time. If none of these are clogged, one could remove the float level needle and remove the fuel hose, and spray some carb cleaner up the channel where this needle sits when installed. Place the plastic straw that comes with such aerosol cleaners right up in there where the needle belongs. Spray a short burst or two up there; a rag held around the rest of the carb body will help keep the resultant discharge of spray out of your face, etc. This process will back-flush the passage from the fuel inlet to the float level needle.

If any screens and the fuel hose were clear before and you still had only a drop-drop of fuel coming from the float needle, then fuel should come out now at a noticeably quicker rate once the needle and float are put back on. And of course, check to see that lifting the float upward softly & releasing it will stop & restart the fuel flow.

This method applies to any small engine and not just Seagulls, in case that helps.


-Ted

give the carb a clean, they are easy to pull apart,

Ditto to all the above. I have experienced it with my 40+, probably triggered by a slightly dirty tank. This tends to clog either the in tank screen or the filter in the line. I also once had the carb loosen just slightly and allow air intake. Choked it worked ok; less air for less fuel. Sometimes I could limp it along by priming to compensate for slower fuel flow or higher air intake. A clean, properly fastened carb should do it.
Good luck
jhartrc