Tundrahog

Ran my boat this weekend. New M5 install. Got one tank thru 80% throttle or less. Water pump works when at idle at the shore line and at home(bucket'o water). Took her out having fun.....steam starts coming out of the water jacket(head) port on the side of the boat. Brought her back in...yep steam shooting out. Did not shut her down...5/10 seconds later while at idle on the shore the water pump starts kicking out water.?. I could tell the motor was over heating, top end wasn't even there.....no rev's. Blew air thru the lines and rudders(Aeromarine) no clogs. She kicks out water at idle all day long. Motor running to hot, pump can't keep up, need some direction guys.....Thanks!

Running Amsoil Saber, 6.5oz to one gallon 87 octane. Looking at the plug she was on the lean side for the first run. Fattened up a bit for the next runs. Nice color on the plug after that.

Scott Schneider

What engine ? .... if a zenoah, drill out the water fittings restriction.
Make sure water lines are Ex-large size and pump close to impulse fitting as possable.

Tundrahog

Zenoah, BJ55. Have not moved the water pump yet....that is on my list. This week..... Do they make larger fittings, or just drill them out? How much can I drill out? This is my first RC boat....not new to RC. 17 planes(nitro/electric) and four heli's.

Thanks

martno1fan

If you look inside the nipples on the head they have a restrictive rim inside just drill it out i think a 1/8" drill bit is what i used,just match the diam of them and drill to remove the rim and open them out.Make sure you use the correct type of tubing for the pump,by the way have you tried running it without the pump to see if its the pump thats restricting the water flow? seen that happen a few times.The pumps only working at idle once the boat gets under way the piccups take over and overide the pump.
Mart

wildman51

make sure that your water pump hose is no more than 5 inches from your pulse and make sure your hose is not sucking together and it is possible to have a lean run and the temp of the engine overrides the cooling and we have steam which has more pressure than the force of the water and then we have no cooling water this has happened to me once try to fatten it up a bit and try it let use know if we helped .wild

Dockman

My BJ55 does the exact samething. I just figured it was normal and have not paid much attention to it. I have run it several hours this way (I never run that hard for more then 15 seconds at a time wot) and have not ever noticed overheating. I have my pump relocated to less then 5" from impulse. What should the temperature be on these motors? I will drill my fitting today and see if that helps?

hibby

Dockman and Tundrahog you are both running aeromarine rudders did you cut that taper off on you rudders that runs vertical? (front part of the rudder closest to the boat). If not, when you get up to speeds around 38 and up the water will hit that taper and force the water to go around your pick-up hole on the rudder. Aeromarine didn't send me a sheet saying that when I got my rudders and when I called them about what my boat was doing he said that was the problem and they send out a sheet stating that with your rudders. Just thought I would check as that could be your problem.

Dockman

I assume you mean where the rudders flatten instead of coming to a point?

hibby

correct. where they start to thin out.

Dockman

Filed my down this afternoon. Found crank bearing issues before I got a chance to test it out. I have ordered extra large water line with the new bearings.

Dockman

Filing the edge off and the groove on out to the edge seemed to fix my problem.

Tundrahog

[:@] Ran the boat today.....drilled out the fittings on the water pump/head/rudder, cut off the leading edge of my Aeromarine rudders as instructed. Still having cooling issues. Switched back to the stock pickups....no cooling issues. So, switched back to the rudder pickup and did right turns only......no cooling issues. Started left turns only....motor started to over heat and cut out....

Took off the rudder and put it under a thick stream ot water in the shop sink. Nice output stream of water about 8 inches. Turned the rudder so the pickup was on the front side of the stream....nice output stream.....turned it so the pickup was on the back side of the stream/rudder....output stream dropped to a trickle. Guess these rudders are good for right turns only.?. I do not race....waste of money for me.... Any rudders out there with pickups on both sides?

PEERPSI

I'd check to see that you have your rudders nice and parallel. I use the Aeromarine rudders in my BJ55 running speeds up into the 50's and they work fine. I don't run the water pump though. Have you tried opening the water pump to check for debris? YOu should also pull the cooling head to check for debris as well.

You will definitely get more flow turning right but I get flow straight and a little when going left.

I get steam out my pipe when I stop as well but that's normal. You no longer have water flow at that point so eventually the hot pipe boils the water off.

I've been meaning to try and drill my fittings for extra flow as well.

glennb2006

As you are not racing it would imply that this is a fun boat only, if that's the case, then you can get away with just fitting a slightly higher drag, but dependable, transom mounted water pick up or, alternately, a prop blast pick up. I'd actually be suprised if you notice a performance difference, other than the motor not overheating.

You should get plenty of water from there!!

Glenn

painman

You might concider adding another water outlet on the cooling head, by adding another outlet really allows more flow of water due to less restriction. If after drilling the existing fitting and still not getting enough cooliing then you might try the second outlet. Drill the fitting out with an 1/8" drill bit.
If adding another outlet use a 10/32 fitting and drill with a number 21 bit and tap a 10/32 tap. This should take care of any cooling problems you might encounter.
Also you can take a small pointed round file and work on the intakes on the rudder, just open up wider and cut grove closer to the front edge of the rudder. This will also help with water intake and better cooling either direction.

Good Luck; Randy

MrMikeG

Just cut another slot in the otherside of the rudder! Simple and effective.