I have a 1990 70 hp yamaha engine was running

If the fuel pump IS working, and it runs on starter fluid. then the carburetor float may be stuck or the jet is stopped up.

Hi, most likely cause and the easiest to check is exhaust leaking in the engine compartment. Run it without the seat fitted for the same time frame and if it fixes your problem you are looking for an exhaust leak. Regards Phil.

i have had this on mine and it was a sort of insect that made a mud nest in the small hole and it blocked the hole up ,try poking it out with a bit of wire

i had to run a inline fuse on my bike with a 15 amp fuse, but there is a short somewhere. check all connections at solenoid make sure nothing is touching

If the bike has sat for a long period of time without being run - the gas that is sitting in the carb(s) will shellac.. Then the carb(s) would need to be cleaned and "rebuilt"..

boston walyler and a yamaha j650 is a good set up

all you need at the moment is a led test light and a volt meter
make sure you have volts or amps and earths at the right places

some messy DIY wiring done and takes time to sort it properly

i would suggest a compression test on the motor

you have water pump impeller worn or coil ,plugs, fuel supply and other reasons why the motor would over heat or run rough

no temp shut down system on yamaha electronics module
if that was blown the motor would not start

this is the boat and the motor yamaha J650c

With the newer yamaha jet boats your route of easiest resistance is gonna be to take the boat to a Yam dealer so they can put a diagnostic machine on it. Alot of sensor problems can be solved much easier and cheaper after running the diagnostic and pinpointing exactly what the issue is. The lights on the dash are for high temp and low oil. If you checked the water temp and it seemed ok, check your oil levels.

if plug is wet or sooty check air filter and replace if it is dirty,also check that choke is opening fully.If plug is fouled you may need another one,