[Luke-Jr]

Engine blocks machined with limited or no cooling jacket can result in steam pockets and hot spots. Boring is great for getting more power out of your engine but notorious for contributing to overheating. At idle the creation of a hot spot at the top of the cylinder may be enough to cause pre-ignition. In the extreme, steam pockets can lead to detonation (hot spots in the cylinder wall) and detonation leads to broken parts. At high rpm the coolant moves through the block fast enough to prevent any steam pockets from forming. FlowKooler pumps flow more coolant through the system at low speed and simultaneously raise engine block pressure 22%. This helps prevent their formation of a steam pockets and suppress es engine hot spots caused by them. more

[federk]

"But wait a minute, I know Grandpa' used to put washers in his flathead to slow the flow and cool his engine." We know people did this too. They still do it but the cooling benefit is not from the slower flow but the pressure that builds from the restriction. Consider that Grandpa had two flathead water pumps sending twice the volume through the same size radiator core. In a non pressure system he likely lost fluid on the track or road. We have use pressure caps since the late thirties to remedy this.

[nadav001]

Ask Grandpa and he might tell you his overheating woes came when he tore up the track at high speed. The overheating could be the result of cavitation in his pump due to the higher rpm.

[Dave Kimble]

A poorly designed water pump casting and impeller can result in wasted horsepower. FlowKooler pumps are designed to move water more efficiently from the radiator to the block to keep you cool. Some refer to the improvement in flow efficiency as a gain in horsepower, other call it a conservation of horsepower. Whatever you call it, FlowKooler pumps are 32% more efficient than OEMs which means less horsepower is used to turn them. here

[books_kabuki]

Re: Steam coming out of exhaust!! [links]

[Confiscative]

Re: Steam coming out of exhaust!! here

[lachesis]

The raw water pump impeller is the first place to look. The impellers on the Alpha I's, MR's and R's were only good for 2 years max.<br />How old are yours?

[h4ck3rk1ng]

heck. i don't know? i bought it from a friend who only had it a year. i am putting a new lower unit on tommorow so i will probably be right there close to the impeller huh? but, would this cause the white steam to come out of the exhaust?

[david718]

Re: Steam coming out of exhaust!!

[jrrr4518]

Re: Steam coming out of exhaust!! more

[planetPlosion]

After speaking with their mechanic i took it in for them too look at it, here

[lockie]

Re: Suzuki DT4 Cooling Problem

[grrrl]

Re: Suzuki DT4 Cooling Problem here

[Davex]

Have you or anyone changed the impeller recently?
I've heard of similar symptoms when the impeller drive pin was left out. Enough drag between shaft & impeller to pump a bit at idle but when running faster the driveshaft just spins in the impeller due to the increased load.
Grasping at straws but might be worth checking.

[hewhocutsdown]

Anyway if you blow in the water tube that might give you an indication of where the water is going, plus by removing the big slotted bolt will tell you if the water tubes around the engine are blocked, the slotted bolt is look at the engine with the prop facing you, follow the leg up and its in the center of the engine at the top, just under the power head, if i havnt explained it well enough then i will add a picture of it. [links]

[cbrendanjarvisi]

Knowing what I know now this will be a mod I will make to every Yamaha I ever may own, even if brand new. Dont hesitiate to buy custom units from Impros. They were great to work with.

[PillipDipper8S]

With the boat I am not sure it would be worth the time or money. Has anyone but the cavitation kits on our boats? I did that on a yamaha PWC once and it seemed to help not get so much air in the pump. With these boats cavitation doesn't seem to be an issue but I do wonder if it would do any good to seal everything up around the grate. here

[adhocimperium]

The following will sound like I'm being paid to write it, I am that happy with my new impellers. They were an amazing improvement to my boat. I did lose maybe 2MPH off the top end, but I dont really spend much time trying to prove differently because I could care less about going over 50. I brought it up to 50 with the new props and called it good. [links]

[mhatta]

I had Impros custom pitch a pair of Solas Concordes. They pitched for no top end loss and a large improvement in acceleration. Mel is right, you cant have it both ways when adjusting pitch on similar props, but the difference here is a more efficient impeller design that bites much better and much smoother than stock which equates to a significant holeshot improvement with very little top end loss. The difference in acceleration was very noticeable! I had around 120 hours on the old units and now 30 on the new ones. [links]

[Marsianin]

I selected a solas for my ski with a pitch change for a better hole shot. I lost about 2mph on the top end.

[awwright]

I agree. I have changed out impellers on a few PWC's I have had over the years. They make a decent difference and changing an intake grate can also help some in addition to the impeller. here