When to change carb gaskets and float

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When to change carb gaskets and float

Post by Phil » 27 Jul 2018, 15:01

Towards the end of a recent trip to Cornwall, my outboard started stalling under load and, eventually, at idle. It was also occasionally leaving a bit of a petrol/oil slick in the water. Having read up that this was probably a sticky carb float or blocked jet, I found the trick to keep the engine operational was to flutter the choke when putting the OB in gear until the revs had built up.

When I got back from Cornwall on Wednesday, I investigated the fuel system. I took apart the fuel pump, which looked fine, but noticed a split in the fuel hose going between this and the carb which I think was probably the main culprit. I snipped the split hose and reconnected it to the carb with a new jubilee clip.

Whilst the fuel hose was probably the route of the issue, I cleaned the spark plugs + removed the carb and cleaned and stripped it as much as I could to be sure. I couldn’t remove the float pin without braking/replacing it – it looked like it was plastic vs the metal pins on older models I’d seen in youtube videos.

I was expecting that I was going to need to spend £50 on an OEM carburettor rebuild kit, however – with a bit of cleaning (see slightly scummy gasket in picture) – the gaskets and float looked fine. There was no gunk elsewhere in the carb (e.g. the float bowl). I sprayed the carb jets with penetrating oil and pushed fishing line and blew air through all of them.
Reassembling everything, the outboard now runs as sweetly as ever, which made me question at which point should you buy a carb rebuild kit and change the gaskets and float? Would you only do this if the gaskets were deteriorating/leaking or the float wasn’t level? I’m very happy to not spend another £50 if I don’t need to!

While looking for parts online, I also noticed you can pick up Chinese-made replacement units like this fuel pump for much less than the OEM gaskets and diaphragm-only part kit. Interesting to consider, although I guess the quality may be questionable with aftermarket stuff:

https://www.ebay.co.uk/itm/Fuel-Pump-Ga ... 2478659796
F-RIB 360 with F-RIB wheels, seat cushions and bag and Scotty rod rests
15hp 1992 Johnson GT 10 2-stroke

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