Water Tubing Q.

[helidan]

I'm going to be re-plumbing the Blackjack and was wondering if 4mm id tubing is ok going over 5mm barbs? The standard Proboat tubing appears to be 3mm id.

Also on the subject of cooling what would cause the cooling water to stop flowing when the boat is at speed but start flowing again at half throttle or less? Something I noticed last night, motor/esc temps seemed unaffected.

[grsboats]

For a very short period it won't be a problem but you need to find what is causing this interruption.....is the water pick up on the rudder deep and large enough?a large tubing is better but don't forget to use tye wraps.Gill

[helidan]

I did try filing and smoothing out the slots on the rudder and also tried slotting the motor's cooling jacket nipples which did appear to increase the water flow but I'm still not totally happy. My mates Pursuit flows good water all of the time although he is using a second water pickup.

I've got some 3.2mm id tubing on its way so I'm going to re-plumb the entire boat and also put the ESC first in the loop. If this does not improve the flow then I'll be looking at a different pickup arrangement.

[Norwest]

Jan of Sneed, Netherlands says to use long lengths of brass or aluminum which will increase flow by x-amount. You know it takes a small amount of water to cool. I put restrictors in exit line, so more heat is picked up but also entrance to cooling jacket should be very close to bottom. The exit on top to rid air which is in the water + bubbles. I'm just passing this on as it is a pro and con subject and each boater can make up his own mind. Have a good day. I don't take credit for this, just passing thru.

[helidan]

Never thought about swapping the motor's inlet & outlet, I guess it makes sense to have the bubbles etc. escape at the top.

I filled the rudder slots even more earlier as well as polishing them with some wet-and-dry paper and I had much better cooling flow this afternoon. I didn't notice any loss of flow apart from when the boat was running very slow. Motor and ESC were barely warm and I could easily hold my tongue on them!! This is with 7.5deg. timing.

I did take a nasty chunk out of the gelcoat today, not sure if it happened when the boat fell of the stand or if I hit something in the water. Need some gelcoat filler now!!!

[flraptor07]

Deffinetly on your water jacket you want the inlet at the bottom and outlet on top. I always run seperate cooling to each component, one pickup and outlet for the motor and one pickup and one outlet for the ESC