To prime the ski before starting - take of the overflow/return pipe off the crb and blow into it. Use a rag to catch the gas. Seem to get them going 9 times out fo 10 if they don't have any other issues.

They should start right up if primed - don't need a primer. The channel from the fuel pump on the carb to the overflow that goes back to the tank should be blown out when you're rebuilding the carb.

Get rid of the oil pump. The pressure the pump builds up forces the oil into the crank area and then when you start the ski after a long winter it pukes oil all over the ground. Use a long screw to seal up the tank pipe. They seem to run better on the 50:1 premix.

If you have no spark or intermittent spark check the flywheel key - if it breaks then you will get that symptom and often a spinning sound after the ski is started.

Get a new solenoid off eBay for $10 and install it - cheap insurance that the ski won't start clicking. Clicking is a sure sign that the solenoid is done.

Check the electrical connections (white pipes that screw into the motor / ebox) on the motor and ebox to see if the fitting are broken - they often are broken and are pretty hard / time intensive to fix b/c you have to take apart the small connector or cut and rewire.

Check any hull for the cracks around the midshaft housing - they are often broken on skis that have been ridden hard.

When putting the tuned pipe on the exhaust put the rubber pipe that attaches the to the water box all the way forward - then you won't have to fight it putting the pipe in.

Skis have to be water tested - don't sell one without doing it b/c it will almost certainly need to be tuned before it will pull a rider up. Jetting is all over the place but can start at 2 out and then go in to lean out.

If the ski wont pick up at all when in the water (and engine seems to be running ok) it probably is the impeller.

Props are easy enough to get off but you may break it if it's stuck - try using a bicycle tool with the pins in it.

The JS440 impeller works great and has the added bonus of having a nut moulded into it so you can easily remove it. The 300SX impeller is made so a special tool is required for install and removal.

The alignment on the pumps is super intensive. The often have a little scraping when you put a new impeller in.

Starters are very hard to find. As starters are not made anymore or easily available - keep a spare one if you can find it on eBay or PWC forums.

Fuel / cap / hose attachment on hood is very hard to find if broken. Can make something that works with hose and JS300 fuel attachments.

Hood seals are very hard to find.

Change the Start / Stop switch to a modern version from a TS650 or other similar era ski with a lanyard. You can use other Start / Stop switches (round start button type) but you need to rewire. KAWASAKI ST 750 JT-750A JT-750A1A START STOP THROTTLE 32099-3767 works.

Change to a trigger throttle is moderately hard to do - can use a KAWASAKI STX 1100 900 trigger. The plastic cover over the handlebars is kind hard to get the trigger cable to work smoothly.

Add a layer of softer under foam if doing the tray with turf.

JS300 coupler does not work in 300SX skis. Too long.

You can replace the choke cable with one from a bicycle brake.

Check the hull for cracks - leaks on the side - bondline of the hull if it has seen a lot of use.

Old type flush adapter (garden hose) is rare on the skis.

If you have the engine out - change the starter gear oil - easy to do and keeps it fresh.