Yamato Question

I have a new, at least to me, Yamato; however, I having some trouble getting the most out of the motor. For start, I get on plane as smoothly as a JSH. Once on plane, I'm fine up until 60 mph, and then it is as if my motor is punched in the gut. It feels as if the back of the boat lifts up for about five seconds, the motor drops to 57 or so and the the motor gets back into the groove and the same thing happens. What could be my problem. I have been told maybe a bad coil or mis-adjusted carb.

[Jack Stotts]

Yamato Question

I had a similar problem at one time and it turned out to be not the engine but the boat. I'll explain. As the boat planned off and was running well with the sponsons out of the water, the boat would lose it's lift in the front and the sponsons would drop to the water thus making it feel as though the rear was coming up. The increased drag bogged down the motor. The motor seemed to surge.This especially happened going down wind. The solution was to trim off some heigth on the air traps near the rear which trapped less air at the rear of the boat. Jack Stotts at jstottsmk@aol.com

[Bill Huson]

Yeeks!

Are you sure you don't have one of the "Danger Cs?" Those were two CSH boats me'n Dave A dersigned and built. They were fast as stink on acceleration but right at top speed they would lose it, sometimes leaping up and jumping over an entire lane. Many changes to air traps and what all didn't cure them. Worked great with an old 30 Merc that had an actual racing gear foot as opposed to the Yamato club foot. Sold mine to a raver racer with an old Merc.

[DougMc]

Not the Boat

100% its not the boat. The boat works fine and dandy with my other Yamato, so it must be something in the motor.

[Fast Jack]

102

Doug ,try another foot on the motor, it may be generating lift,causing a problem getting up on top . The one you are geting from me was done by Tom Cronk and works very well , Shawn

[David_L6]

100% its not the boat. The boat works fine and dandy with my other Yamato, so it must be something in the motor.

Are both motors identical? Have you tried swapping the lower units?

Try getting in the very back of the boat... Use an extension if you need to so you can get further back. Try to keep the front end up and the back end planted.

[DougMc]

Doug ,try another foot on the motor, it may be generating lift,causing a problem getting up on top . The one you are geting from me was done by Tom Cronk and works very well , Shawn

Your motor arrived today - thank you. My next trip to the lake will be this weekend, I will take the foot from your motor and try it on the motor I am having trouble with.

[DougMc]

Are both motors identical? Have you tried swapping the lower units?

Try getting in the very back of the boat... Use an extension if you need to so you can get further back. Try to keep the front end up and the back end planted.

Yes, they are the same. Never though of that, but will try swaping lower units. Maybe I'll try an extension too.

[888race]

Doug

You KILL me

[DougMc]

Carb.

Turned out to be the carb. I moved counter clockwise 16 clicks and she now runs well. No more bogging down and picked up some punch and mph.

[Dick Tyndall]

Fuel mixture...............

Turned out to be the carb. I moved counter clockwise 16 clicks and she now runs well. No more bogging down and picked up some punch and mph.

As we say in R/C model boat racing, "Lean is mean, but fat is where it's at".

[DougMc]

It is amazing how such a few small turns of the carb. can make so much of a difference. I felt like I was in a different boat.

[Bob Dunlap]

Turned out to be the carb. I moved counter clockwise 16 clicks and she now runs well. No more bogging down and picked up some punch and mph.

16 clicks? Doug 16 clicks isn't a Small adjustment, that's BIG