jetmotor running on trailer

moark · Aug 4, 2011

Can anyone tell me how many rpms I can run and how long with my jet in the water and on the trailer? Need to make some adjustments while motor is running.
Thanks in advance for any replies.

Ranchero50 · Aug 4, 2011

I think you'll have trouble running high rpms on the trailer. I suspect it'll suck air and cavitate. Running it out of the water isn't going to be good for any adjustment. My idle changes from 3200rpm in air to 1500 in the water. I didi set that and idle mixture on the trailer once I broke the engine in.

You should be able to have someone steer the boat as it idles up river while you check the idle mixtures. Going to be a pain on a multi carb engine. For other checks running 3/4 throttle for a minute and doing an ignition chop is best, then check the plugs to make sure they are slightly rich before doing a wide open run with throttle chop.

First time I did that the kids about rolled off the front of the boat.

Jamie

bulldog · Aug 4, 2011

I would think you can make minor adjustments on the trailer but you will never be able to make high rpm adjustments. Ranchero has it right when he says to have someone steer and adjust on the water. It is going to be a pain no matter what. Is it worth $100 to take it to an professional? I think it would be for me but I'm not very good with carbs other than idle adjustment.

Lil' Blue Rude · Aug 4, 2011

You can make adjustments on the trailer just set the parking brake on the truck when it backed in back the boat in just far enought hat the shoe is in the water when the motor is trimmde up like your going to spray a rooster tale. You can make high speed adjusments and everything no problem. I've done it and a local high performance shop does the same thing. You can set the timing and high speed sets.

moark · Aug 5, 2011

Don't want to sound stupid, but what is a throttle chop?
Thanks everyone for all the advice and replies.

Lil' Blue Rude · Aug 6, 2011

Think he's talking aboout checking the burn of the plugs to see if it's rich, lean or spot on. You run it wide open for about 5-10 seconds then you turn the key off while it's still running wide open, this way you can see what the plugs read at high rpms.