Saturday, 13 April 2013

Lawn mower service

Serviced Ralph and junior.  2 days!  
Junior.  Stripped down to deck, 1 coat of hammerite.  Some oil leaked out of the exhaust as I stored the engine plug down (should have been the other way)
Ralph.  Repaired brake, greased, made pin / drilled for pedal, re-fitted original broken spring which was weaker than the replacement in the drawer.  Welded deck, fitted some straps, hammerite & filler.  Wouldnt start, but this might have been pilot error on the choke set up.  Then the float stuck and fuel leaked over night.  Suspect float had weeped over winter as there was a slight patch on the floor
Oil clean on both, so not changed.  Cleaned plugs.  Both a bit black.

Following day decided to inspect Ralph's carb.  Found a blade of grass in the float valve.  Cleaned this and the fuel tank.  Carefully removed main jet and used lm grease on shaft to help seal it against the rubber seal.  Replaced it all, but no new gasket for the bowl.  It weeped a bit when moving, ok stationary as the float level is below the top (?) Ralph just wouldnt start - spluttered once (used a large external battery and 20A PSU on jump leads direct onto motor.)  Cleaned the plug (NGK BM6A) and he started straight away and ran.  Set up main jet, but then he wouldnt restart.  Took the plug from junior (Champion RJ19LM - original).  Different part number put same length internally, much longer externally, and easier to get in being longer.  Started first time and every other time.  Took off air filter and set up idle revs and mix.  Mix too rich and idle too low.  Both idle and main jet at 1/2 turn ACW from fully screwed in.  Both had been too rich.  Runs well, starts well, operated under load fine, no backfiring or hesitation.  Oil leak from carb breather at low revs.

Refitted exhaust with a little gasket paste.  Bit quieter now.  The block is threaded presumably to take the screw in exhaust.  Also removed bowl and re-fitted with a tiny wipe of gasket paste, although it's not recommended for immersion in fuel (fuel level is, I think, well below gasket)

Carb float hinge is on RHS (from rear) so raising the rhs will cause level to drop as the RH side of petrol will keep the float high.  Tilting the lhs will cause an over flow.  Ralph is impossible to start when RHS is high.

RH looking from rear tyre, which has always been a pain, was flat again mid winter and once the bead had broken, it wouldnt stay up.  The valve was leaking too.  This tyre had sealed ok with pva and grated rubber.  Couldnt get the tyre off without worrying about breaking the steel band, so managed to get a wire wheel into the rim and cleaned all the rust off the bead on the rim.  Re-sealed with boos white on the rim and valve.  All ok.

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