Kevb

I'm building a boat at the moment powered by a G260 with a clutch so obviously I'll need some kind of pump for cooling when the engine is idling, problem is I don't want to start drilling the block to put the nipple in for a vacuum system. Does anyone know of a small electric pump that I could operate by a microswitch on the throttle servo? Possibly using a 6 cell Nimh pack or similar.
One option is to use a car windscreen washer pump but I don't know how effective it would be on 7.2v, also it's size and weight would be a big factor too. There must be a small dc pump available somewhere.
Anyone any ideas?

Cheers,
Kev.

BMAD01

Ya do'nt need to drill into the block! Zenoah's have a "pulse fitting" on the underside of the insulator block. Yano that lil plastic spacer thingy between the carb and cylinder. Brian

OLD_SLOW and in the WAY

zenoahs dont come with that fitting stock....a washer pump wont last long at all they are made for intermittent use....there are "smoke fluid pumps for rc planes that run off 6 volts ..unless you have a voltage regulator dont run a 7.2 v pack through your receiver...you will let the smoke out of the components renedring it useless....water will flow the engine even at slow speeds so unless you plan on just sittin there idlieing why use a pump at all

Kevb

So I could drill into the plastic spacer the carb is on?
I wasn't intending to run the rc gear from 7.2v, I as going to use a pack soleley for the pump. The idea I was working with was to use a microswitch on the throttle servo that would operate the pump when the engine was idling and switch it off when the throttle was opened.
I'd feel a bit worried about the engine overheating if I didn't have one as there would be zero flow through the system when the boat wasn't moving.
I'll look into the smoke fluid pumps though, they must be quite small and light if they are designed for planes.

Kev.

tatolazo

You could go to an R/C airfield club or contact some airplane fellow and ask if the regular electric glow fuel pump can pump water. I think it cpuld perfectly. Since the operation is very simple and water would not destroy the inner parts they should serve the purpouse as well and are a lot cheaper than a Smoke Pump. The idea of the switch coupled to the thr. servo is also good, simple and reliable.

BUT..... Did you think if the water would run through the water line to the cylinder by itself alone once the pump is off???? May be you should place and "Y" connector before the cylinder head and use a separate water line for the pump, taking care that it do not return by the other line in the opposite direction of the cylinder head, flowing way by the intake.

(Hope I make my point clear)

Also, I seems to me that Walbro sells a pump, it looks like a 1/3 of a carb since it it just the pumping portion of the carb that uses the same method...the crank presuure.- This way, you can set it pumping all the time...

Aaronie

You don't need so stinkin' PUMP. Well, only if your going to be idleing the boat in the water for 2 minutes. Larry got it right - water will flow through at slow speeds. Save your money, there are better things to buy then a water pump.

Kev_B

I'm fully aware that water will flow through at low speeds, but, unless the laws of physics have changed recently, when a boat is stood still the speed is ZERO and the little water molecules aren't going to take it upon themselves to swim up into the water intake and around the system! I know that it won't matter for a very short period of time but I can't guarantee that each time the boat is stationary that it'll be for a very short time, it has a clutch fitted so occasionally it will be sitting idleing for more than two minutes, the capability is there so obviously at some stage it will be used. Hence the thoughts of including a water pump at the building stage rather than having to retro-fit later on.

Tatolazo, I had wondered about the through-flow when the pump wasn't switched on and had considered fitting an extra line in, like you'd suggested, but with a one-way valve in it to stop the water from returning down through it. The only problem there would be would the valve inhibit the flow too much when that particular line was in use? I reckon it's just a case of experimenting, and if all else fails get the drill out!

Kev.

OLD_SLOW and in the WAY

a pulse pump will over ride if the water coming in is greater than the pumps capacity

tatolazo

I remember than in the Aeromarine RC web site i saw a walbro water pump alone. This one could be set with the cranck pressure and working all the time, so the pumping will be porportional to the rpms i the engine, what could be best??

Only I don´t remember the adress but yahoo can do it for you.

Hope this can help.

tatolazo

Here is what I meant. from rcshark.com

skoda450

All,... A water pump is not needed when everything is working correctly. Even an engine with a clutch is OK because the boat doesn't sit motionless for very long, again, with every thing working correctly. A pump will, however, save your engine in the case of a radio failure or drive system (prop loss etc) with the engine still running. If it is idling the pump will keep it cool. If you have no clutch it will still save your engine if the radio fails and the boat runs it's self into the weeds and the engine keeps running. I know of this happening and the engine was a complete siezed mess before the boat could be retrieved. A battery system is not a good idea because it can run down when you need it most and adds another failure mode. Think of a pump runing from the engine base pressure as insurance. At the risk of sounding like Yogi Berra "You don't need it, until you need it!" The Walbro pump offered by Prather is reliable and if the engine is running and needs water, its working. A blocked inlet is still a failure mode but that's a problem for ANY water cooling system.

tatolazo

Skoda450:
After all you are right. I heard from World championship R/C areobatics,Quique Somenzini, when I asked him why he don not use the fueling valve from Dubro and instead had those ugly fuel lines hanging from the cowl of his 1/3 scale Laser 200:

He replyed: "What you do not put in.. do not fail!!!

What can you say to a truth like that???

Tato Lazo

Kev_B

The reason I was considering an electric pump is because I do not want to drill into the engine block to fit the pressure fitting for a vacuum pump, it's a brand new engine and I don't want to invalidate any warranty before I've even started it up.
I'm not going to install an engine equipped with a clutch and not have some form of pump to circulate water when the boat is motionless, whether because I choose to have it sat still in the water or whether it happens through something beyond my control. Bear in mind that over here in the UK it costs the equivalent of over $500 for a factory stock G260 so I think it's a bit stupid not to build in some kind of safeguard, don't you?

Would I be able to drill into the black plastic spacer/insulator that is between the carb and the engine to put the pressure fitting in there? Or would it interfere with the passage of the fuel/air into the engine?

Kev.

Captain Ramius

I can understand your concern over a windscreen washer pump, especially if its made by Lucas,if this cooling issue, is such a problem maybe you should consider an alternative to a gas boat,maybe just an electric boat they will sit still for hours without any problems.
While you working on a solution to the cooling issues ,think about how your going to pump out that water dribbling in through stuffing tube whilst your contemplating your next move and boat is motionless on water.
Auto bailers move be a solution but they need the boat in motion to work after idling for a long period of time 2 strokes have a lot of oil built up in the crankcase,applying throttle often results in a flameout due to a fouled spark plug.

Kev_B

I don't think I'll even give that the benefit of a response.......

I'm beginning to regret asking if anyone knew of an alternative to a vacuum pump

Of course, you're all right, how stupid of the British bloke to be concerned that his engine may overheat, that'll never happen will it because we all use our boats in exactly the same way and no one should ever even consider that their boat will be stopped long enough without any cooling to cause damage. How daft could I be for thinking that......

Captain Ramius

Guess you never saw a boat sink from water coming in stuffing tube.......
everyone has offered good ideas and suggestions,all of them seem to be a big problem to accomplish or unacceptable.
Chances are the warranty expired on your motor anyway, 3 months or 1 year from time of manufacture, so punch a hole in it and hook up a pump.

Kev_B

I guess not, but then that could be because the people I go boating with have been prepared for things like that before they happen by installing some form of flotation in their boat, kind of like installing a water pump before your engine has overheated.

Really? Read my original question again, then see how many of the 'good ideas' actually answer what I asked. I appreciate the ideas and suggestions from those that have, but nowhere have I said "Should I fit some sort of pump or not?" Sure, everyone is entitled to their opinions, it's be a boring place if we weren't, but I'm entitled too, remember. Are you saying that I should ditch the idea of having any form of pump because that is what a few people here have said?
As far as all of them being a big problem to accomplish . . . Which would they be? Are you meaning the single fact that I don't want to drill through the block? I'm sure I mentioned that right from the start and it hardly equates to 'all'.


Anyway, I don't want this to degenerate into a slanging match, nor do I wish to cause any ill-feelings so I won't continue, instead I'll try to sort out my cooling problem, that is if anyone is prepared to talk to me.


Could anyone please tell me would I be able to drill into the black plastic spacer/insulator that is between the carb and the engine to put the pressure fitting in there? Or would it interfere with the passage of the fuel/air into the engine?

BMAD01

Gee, maybe I'm wrong about this. Then just what is that fitting underneath MY insulator block? This obviously is'nt a stock G260, but mine came to me this way from BonsiSports. I do'nt run a clutch, so obviously have no need for a water pump. That's why I blocked it off. There is a small vacume passage on the lower side of the insulator bolck that the fitting go'es into. You DO"NT want the fitting to go into the main passage! Brian

Kev_B

Cheers Brian, I'll take a look at my insulator block and see if there's a passage there I can drill into. Mine came from Bonzi too but unfortunately wasn't modified.

Kev.

Aaronie

If you don't want to drill a hole, don't use a pump. Your engine will never overheat. I've been around boats for 2 years and I've never heard of a Zenoah overheating.

Captain Ramius

A puddle of pot metal on the bottom of the boat is sure sign the zzzenoah overheated.
Its not going to over heat though, its going to load up and stall.2 strokes and idling is not a good idea,especially when you run enough oil to protect the engine at high rpm.
Its a common misconception most noobies have that you can idle all day long I doubt Kevb has run a gas boat much less seen one in person so we will have to give him some leeway,but as he said a few posts up ,he doesn't need our help., so hes on his own.

BMAD01

Hey KEVB, ifin you're gonna run a clutch, USE A WATER PUMP!! Do'nt listen to thems others tellin ya not to! You'll melt the "O" rings in yer exaust, among other things. If ya do'nt have a pulse fitting on yer insulator block, CALL DAN AT BONSI. He'll have you a new one at yer house in a couple "O" days! CAKE!Brian[8D]

By the way, My engine's a BZX-4

stevblutu15

alright guys, im sry but i need to anser this ? in my own view. Get the stupid pump its like 25 bucks. give tony a call at warehopuse hobbies and he will help you through the entire thing. what will this cost you 25 30 bucks? its definatly worth it. i have a funcruiser and running one day the flex cabvle snapped (luckily it was aircooled) do u really think a water cooled zenoah will sit for hours ideling w/o cool water flowing through it? Im telling you call tony up and he will get you set up. he'll give you detailed iunstructions and all. u dont want a big ass electric pump with batteries sitting in the boat any way. and the pump wont harm anything here is the link: www.warehousehobbies.com
this setup works!

Kev_B

Dan from Bonzi sent me the info as to where to drill nto the insulator block on Friday, so it's vacuum pump here I come!
Thank you to everyone who had something positive to say


A Noobie eh? Awww, that's nice, thanks, you've made me feel younger! I've never been called a Noobie before, especially seeing as I got into ic rc quite a while before that term was ever invented, in fact quite a while before the internet was invented, in fact quite a while before the PC was invented......
Experience with nitro.... enough
Experience with air-cooled gas..... enough
Experience with air-cooled gas + clutch..... enough
Experience with water-cooled gas...... enough
Experience with water-cooled gas + clutch..... nil, hence my questions here.

Amazing how some people jump to conclusions (and also seem to read things that aren't there)

Kev.

Aaronie

In the world of rc gas boats it's a very good idea to be able to shut your engine off via the Trasmitter. Take the idle screw out of your carburetor and adjust the engines idle by the servo trim. When you want to shut the engine off, just hit up/reverse on the Transmitter throttle and the butterfly closes. This way...

if your boat malfunctions and it is stuck idleing on that grassy, rocky bank 100 feet away, you can shut the motor off. Or in the case of "stevblutu15" if your cable breaks you can shut the motor off.