Test tank for a 125?

[MYork]

I've read threads where many of you have written,"take it out on the water, and do your adjustments." I understand the importance of doing so, since a barrel filled with water (or a device connected to a hose) isn't adequate for motors over a certain size, BUT, has anyone built a test tank for motors, like a 125 hp? Would one that is 24" wide, deep enough to cover adequately, and about 4' long be sufficient? Where I live, you can't just back into the ramp and sit there, and I'm already facing a fiberglass repair job, thanks to a jet ski wake, from when I was trying to adjust the motor the first time. Thanks! Mark

[Greg Moss]

You will blow the water out of a tank as soona s you put the motor in gear. I would have to have a lid that can be closed and then can run the motor . There is a company call Bob Kerrs that build test tanks for outboards they ain't cheap! I have one about 10' long and 3ft wide and 3 ft tall cut out on the end for the motors to go in. I use it for cooling only. I have a dyno that goes on the prop shaft. If I put a motor in gear the load is not the same once the water swirls the motor is unloaded.

[MYork]

for your reply! They do sound expensive. It was just a thought. So I can assume a 10 ft. length is not sufficient for the water that is being pushed back to "settle down," and not be thrown out? MY

[Greg Moss]

you could baffle it I think and get some settlement of the turbulence but I would not know about how to design that. the Bob Kerr's has some baffles in it but I don't know how they have them in there. I think it is vertical rows of angle iron in on direction and the next row offset and in the other direction can't remember been a long time since I have seen one. I have a dyno that I use in my tank. Or I go across the street to the ramp if I have to run one with a prop. I know you have to have an exhaust out let near the back of the tank and the lid slides about half the length of the top to allow you to put a motor in and had some kind of a rubber gasket to seal around the downhousing to keep the water splash to a minimum. Don't know if they have a site for you to look at one.

[Tom D.]

When I was a kid(dark ages) my dad built one out of a 275 gal. oil tank. Notched here and there put a piece of 2x8 on it to hold the motor and away ya go. I don't see why you couldn't make something out of a plastic barrel and use a test prop. Next time I'm at my Dads house I'll try to get a pic of his test tank.

Tom

[MYork]

the test prop is the answer. I cut a 50 gal. plastic barrel to make a tank, but the prop. shot the water out immediately. I thought with a more rectangular shape, the water would have a chance of staying in. Perhaps if I fashioned a "coffin-like" device, with the majority of the length being covered, then it might work. OTOH, maybe I should take the motor to someone who knows what they are doing! MY

[Greg Moss]

The reason you DON'T run big motors in a drum or a small tank is the exhaust pulses are to violent for the amount of water and it will areate the water to much for the motor to cool properly. Just go to the ramp at lunch time during the week or when the ramp is not to busy. surely during the evening monday or tuesday the ramp can be used. Or you could just take it to someone that knows what they are doing:D