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I would like to provide some recommended checks on the Y302 prior to begining the season, but first let me preface this topic with this is intended for newer racers (and I am in that group), not seasoned racers - but input and recommendations from seasoned racers on de-winterizing/preparing Y302 for the race season is very much desired.
So these are maintenance steps I recommend on a Y302 for de-winterizing/preparing for the upcoming race season:
Check your cylinder compression - low or severe variation in pressure between cylinders may indicate a blown head gasket (easy to repair) or bad rings/severely scored cylinder walls (not so easy to repair).
While you have your plugs out to check the cylinder compression, check your plugs for fouling and gap (manual calls for a .020" gap) - replace if necessary. Also check your timing - manual calls for .200-.250 BTDC.
Flush your fuel tank and fuel line - ensure all debris is flushed out and screen (if you haven't knocked it out) is clean.
Clean your carburetor - at a minimum remove and clean your float valve as debris and gunk likes to accumulate there... also check your float level needle length - manual calls for a length of 1.25".
Remove your exhaust cover (6mm bolts, use a 10mm socket) and check to ensure gasket isn't blown or exhaust cover isn't warped by using a straight edge. A blown gasket or warped cover will reduce power and may cause overheating issues. A slightly warped exhaust cover can be easily trued by taping/gluing some sand paper to a flat surface (a piece of melamine for example) and sand with slight pressure while ensing exhaust cover remains flat to prevent unwanted cupping of cover edges. Use a torque wrench to secure exhaust cover @ 5-7 ft/lbs (spiral tighten to prevent warping). Note - may want to use anti-seize on bolts as they are SS on aluminum...
Check your tuner pipe - remove your powerhead (secured by 6 x 8mm studs/nuts - use a 12mm socket) and ensure tuner pipe is flush with top of lower unit using a straight edge - if tuner pipe isn't flush, yuor gasket will blow and you will experience reduction in power. If the pipe isn't flush, remove the tuner pipe (secured by 3 x 6mm studs/nuts - use a 10mm socket) and place shim washers on studs to achieve right height (TIP - I make shim washers by making them out of a soda can with a hole punch and scissors - they run about 3 thousandths of an inch in thickness). Torque tuner pipe bolts to 5-7 ft/lbs, replace your gasket if necessary.
Change your gear case oil. You may have to flush the gear case if you notice a metallic sheen to the oil - especially if you had a new prop shaft/gears put in... I use denatured alcohol to flush it out - don't want any metallic residue wearing out my bearings early. If your oil is white, you have a leak and water is getting in - replace your gear case gasket. Fill gear case with new oil up to the bump - rotate your shaft a few revolutions to get oil into the gears/bearings and check level again then replace gear case.
OK - anything else I'm missing?
So these are maintenance steps I recommend on a Y302 for de-winterizing/preparing for the upcoming race season:
Check your cylinder compression - low or severe variation in pressure between cylinders may indicate a blown head gasket (easy to repair) or bad rings/severely scored cylinder walls (not so easy to repair).
While you have your plugs out to check the cylinder compression, check your plugs for fouling and gap (manual calls for a .020" gap) - replace if necessary. Also check your timing - manual calls for .200-.250 BTDC.
Flush your fuel tank and fuel line - ensure all debris is flushed out and screen (if you haven't knocked it out) is clean.
Clean your carburetor - at a minimum remove and clean your float valve as debris and gunk likes to accumulate there... also check your float level needle length - manual calls for a length of 1.25".
Remove your exhaust cover (6mm bolts, use a 10mm socket) and check to ensure gasket isn't blown or exhaust cover isn't warped by using a straight edge. A blown gasket or warped cover will reduce power and may cause overheating issues. A slightly warped exhaust cover can be easily trued by taping/gluing some sand paper to a flat surface (a piece of melamine for example) and sand with slight pressure while ensing exhaust cover remains flat to prevent unwanted cupping of cover edges. Use a torque wrench to secure exhaust cover @ 5-7 ft/lbs (spiral tighten to prevent warping). Note - may want to use anti-seize on bolts as they are SS on aluminum...
Check your tuner pipe - remove your powerhead (secured by 6 x 8mm studs/nuts - use a 12mm socket) and ensure tuner pipe is flush with top of lower unit using a straight edge - if tuner pipe isn't flush, yuor gasket will blow and you will experience reduction in power. If the pipe isn't flush, remove the tuner pipe (secured by 3 x 6mm studs/nuts - use a 10mm socket) and place shim washers on studs to achieve right height (TIP - I make shim washers by making them out of a soda can with a hole punch and scissors - they run about 3 thousandths of an inch in thickness). Torque tuner pipe bolts to 5-7 ft/lbs, replace your gasket if necessary.
Change your gear case oil. You may have to flush the gear case if you notice a metallic sheen to the oil - especially if you had a new prop shaft/gears put in... I use denatured alcohol to flush it out - don't want any metallic residue wearing out my bearings early. If your oil is white, you have a leak and water is getting in - replace your gear case gasket. Fill gear case with new oil up to the bump - rotate your shaft a few revolutions to get oil into the gears/bearings and check level again then replace gear case.
OK - anything else I'm missing?