Justaddwata

My Feedback: (3)

I have seen multiple requests for info on tapping a carb carb isolator block for a pulse water fitting both via e-mail and on the forums. Thought I would put something together to help.

The carb Isolator block is definately the way to go, you can also tap the crankcase or transfer ports of the motor but in both cases you must be able to see the inside of each location so you can remove all shavings following the drilling and tapping (you will have to tap the aluminum case as the brass fitting wont be able to create its own thread there).

OK just did one - so roughly 5 minutes start to finish. Slowest part is removing the coil and carb isolator block.

Step 1
Identify optimal location for your fitting. You must tap the lower port (top port is closed). You may want to mark the location as you eyeball it. Also be aware the port in the isolator block does widen so you have more port available to tap the closer to the head you go (but dont go too close)
If you are keeping the ignition coil where it is located from the factory (if your not using a coil relocator) then be sure you have adequate clearence away from the coil with your fitting. Too far forward or central and you may have interference issues). It is also preferable to use as short a fitting as possible (or one that is a 45 or 90 drgree - both will afford more clearence from your coil).

Step 2
Remove Ignition coil and isolator block. Look at the inside face of the isolator block and you can see that the port is wider. Identify the best location to drill for your fitting being mindful of clearence needed for coil.

Step 3
For the nipple fitting I am using a 9/64 drill bit is probably optimal. It will still allow enough material for the brass threads to bite into as I screw it in.

Step 4
Drill at low speed and pressure into the isolator block. Only go as far as the first port hole (not into the intake). Remove drill and debris. Use a smaller drill bit to manually clear any debris from inside the port also.

Step 5
Install fitting. I use pliers to maintain a firm grip while I push and turn it in. It should bite and start a thread. Once started it should screw in and tighten. Be sure not to overtighten - you will more likely break the brass fitting than strip the thread - neither is desirable). Once it is in ensure once again theres no debris in the port. Blow through the fitting and ensure air flows out both sides of the port.

Step 6
Reinstall the isolator block. Be sure the gasket lines up with the port in the head. Once secure. Add your tygon tubing for your pulse line as it may be more difficult to access once the coil is reinstalled. Use only TYGON tubing for the pulse line as the fuel and oul accumulation WILL deteriorate silicon tubing (also diminish the pulse reaching the pump). Be sure to locate the pump as close to the motor as possible. Long pulse lines will also diminish the efficiency of the pulse and reduce water flow.

Worth noting.
It may be necessary to clear your pulse lines on occasion. The air pulse that enters the tube will over time accumulate oil that will inhibit the flow through the pulse tube.

I also install a brass nipple into the water pump. You probably wont need to drill the before installing it. It makes installing Tygon tubing much easier and cleaner. You can also cut the protruding portion from the pump and install your nipple flush with the pump for a cleaner look.

If you make a mistake while drilling the pulse fitting into the isolator block. You can rotate the block 180 degrees and have a second chance at doing the isntallation. The ports top and bottom are identical. Just be sure that your final pulse line is taken from the bottom of the isolator.

Ultimate48

My Feedback: (1)

Hi Matt

Thanks for posting this , I had many people ask me about doing this.

Great job !

Steve

martno1fan

Fantastic Matt this should be made a sticky, or why not make a new forum just for such tips such as how to sharpen props how to fit and tune a tuned pipe etc.Would make things easier to find for the newbies,ive seen this kind of thing done on other sites where you have a forum just for building tips ,setup tips etc etc.In fact theres allready some on here in the plane forums so shouldnt be hard to do.Just an idea as it seems we get the same questions asked all the time over and over.

mopartybob

how come no-one wants to post these great tips and set-up ideas in the RCU University boat section....[:-]

STEVE MARSHALL

I did, yesterday , but this is way better. i am even going to use the nipple idea in the pump.
Steve Hope you dont mind Matt.

Justaddwata

My Feedback: (3)

By all means. Sharing tips and tricks is what it is all about

I will have to look at the RCU University boat section - Never been there [sm=red_smile.gif]

mopartybob

I started a thread a little while back asking people to donate a how-to article or tuning,set-up tip, as the noobies were being redundantly inquisitive,RCUU is relatively barren of any info whatsoever.....[&o]

Justaddwata

My Feedback: (3)

I have asked Admins for details for adding to RCUU. We can get it into shape with a little time/effort

martno1fan

Cool this could save a few people some effort ,i know when i started out i asked all kinds of questions and i bet people get fed up answering the same old question over and over.Ive been asked the same questions over and over regards scratch building and plans and suchlike.Seems you just answer one question and along comes another half dozen newbies all asking the same questions.Ive lost count of the amount of peole who have asked me how i did it where i got the plans etc etc.Ive only been in this obsesion a cpl of years so heaven knows what it must be like for people like matt .Dont get me wrong im allways happy to help anyone if i can and i know most guys on here are too but it can get a bit tireing and a little annoying after a while if you answering the same thing again and again.By the way i still regard myself as a newbie so i still havent finnished asking questions so look out Matt (EVERYONE) lol.

Justaddwata

My Feedback: (3)

Indeed Mart. Like everything these days - there always seems to be something new coming along.

I learn something new everyday - thats for certain. Hopefully not always the hard way


the admins are revisiting how content is added to RCU U so hopefully it will be a little more user friendly.

bentley marshall

some one was looking for this just bumping it up

irenaslavo

Justaddwata, thanks a lot for this great useful post but I have 3 questions:

1-where we can install water pickup and what shape looks like. ( a picture will be great)
2-All my boats without clutches but I’m suffering from overheating, is water pumps are limited to engines with clutch?
3-Is water pump is better than normal water pickup which cooling engine by speed.

Thanks again for your support.

Justaddwata

My Feedback: (3)

Irena,

The most common water pump is actually a Walbro fuel pump that we just use to pump water. There is a pump shown in the pictures aboce ([link=http://image2-5.rcuniverse.com/e1/forum/upfiles/162003/Kj81725.jpg]Shown here also[/link]) which has the part number WIP....

the pump should be mounted as close as practical to the motor as the crankcase pulse is diminished over longer distances through the pulse line.

Water pumps can be used on any boat - with or without a clutch. You can also run a boat with a clutch without a water pump but it is less common as the boat may overheat if sufficient speed to maintain flow is not considered. The boat can run without coolant flow a short period but longer durations idling will cause the motor (and exhaust components that also use water cooling) to overheat.

If your boat is overheating it may be symptomatic of a bigger problem in the system. Possible causes are poor pickup location, water lines of too small a diameter, water lines of excessive length, incorrect tune (Running lean), Running too slow, obstruction or kink in cooling lines, running high octane fuel (Zenoahs are designed to run standard octane). the addition of a water pump may help with the overheating issue you are facing but there may be a bigger problem that is being hidden with the added cooling of a pump that may flare up soon (if running impropper tune or have an obstruction for example - water pump will be a bandaid rather than a cure). Your boat should be able to cool itself without a water pump.

The water pump will need to be used in conjunction with a good water pickup that will cool the boat at speed. What will happen is as the boat runs raster the pump will allow water to pass through the pump with just the force of water alone (pump wont pump as much water as can flow from a good puckup at speed).

irenaslavo

Thank you very much for your detailed replay, I will take pictures for my boats they you can have clear view on my setup but you highlighted very important point( running high octane fuel ) I allows use high octane fuel, I read this DDM web site (http://www.davesmotors.com/store/engineparts.html) , please have a look at (http://www.davesmotors.com/goped-faq.htm) you will find that he recommended for G2D ( my engine before modification) a 91 octane or higher and oil Ratio 1:40 !!!!!! … Please I need you advsie on his point

Believe It

maybe so for the Goped stuff, as alot of them guys are using billet heads with removable button's that allow for some very high compression ratio's. The ignition in our PUM motors isnt up to the task of burning the high octane fuel fast enough to do any good for performance.

Justaddwata

My Feedback: (3)

87 octane and 20:1 has set many a gas speed record. It is what I run (when I am not using White Gas - White gas has an octane rating of 50-55) in all motors with a preference toward Coleman Fuel (White Gas).

Many motor builders will recommend higher octane ratings when timing and/or compression is altered from factory specifications. Higher octane fuels will require more energy to burn (less volitile than lower octanes - think of octane like a combustion inhibitor) and will reduce preignition (also called knocking or detonation) which can occur with lower octane levels in modified motors. The myth is that high octane fuels are more powerful than lower octane fuels - this is in fact the opposite.
For what we are running I cannot imagine needing much beyond 91 octane. Higher octane fuels tend to make our motors run hotter.
I am by no means saying "this is what everyone should do" but rather "this is what I do" - I have run EVERY MOTOR I OWN on coleman fuel and NEVER seen any adverse effects in performance, reliability, or tuning compared to running pump gas. In fact I find motors a little easier to start and running cooler.
I would recommend reading up a little on Octane and what Octane does. I think you will soon find that every piece of marketing by gas stations is the opposite of reality. the general rule for octane is to run as low an octane fuel as possible without experiencing motor knocking (challenge we have is you will never hear motor knocking in a model boat in the middle of the pond). But certainly food for thought!!

Irene - If your running 91 octane you should not be seeing excessive heat generation attributable to fuel - if your running high octane and then dumping in octane booster (as many getting into this hobby do) then it might be wise to mix up a new batch of fuel. As for oil mix - everyone has their recipe. I run 20:1 synthetic or synthetic/castor in every thing. I have never heard of a motor being damaged by this mix ratio and I associate this mix as possibly saving a motor or two that have ended up beached and reving till they die. A little extra oil at times like those is never a bad thing. If you are overheating your motors then I again feel a little extra oil (while not cooling the motor) may be a safer option.

Certainly post some pics of your pickups, routing of lines and exits and I am sure we can help

ScooterTrash

[sm=confused.gif] Hi Justaddwata, Is there any how to's for newbee's like me for boat's, like there is for Gas - Speed Boat's Thanks, PS: Lot's of watter here in Galveston! LOL

irenaslavo

Justaddwata, I attached picture of water pickups, location of my engine, and propeller postion, I will be pleased receiving your comment and please advise if I can install clutch in my boat ( AC King Cat II 44�) or space to servos box is small ….maybe I can move engine to the back and change the engine angle, then I can install clutch.

halls

I have a quick ? for ya do you go all the way throw your do you stop right after that first hole ? thank jim

Dana W

Stop at the first hole Jim .

halls

thanks jim

noahdear

My Feedback: (2)

A pulse pump is not necessary even with a clutch. I wasted my money buying a pulse pump to go with the O'Neil clutch and later found out it is totally not needed.
Danny from Sonicracingaustralia.com told me the facts of using a pulse pump with a clutch when I bought an engine mount from him, and from my experience it is all true. You won't need a pulse pump unless you plan to idle your boat for long periods of time in or out of the water. The motor can handle idling for a short while without water flowing through the head, just as it does when you start it on the bank and carry it to the water. Most people I have witnessed run their boat at speed as soon as it hits the water and only idle it to bring it back to the shore. The pulse pump disengages when the boat is run at speed because the water pressure from the water pickup keeps the pump valve open. SO if you run your boat at speed you don't need a pulse pump. And if you only idle your boat to bring it back to the shore, you also don't need a pulse pump. So you don't need a pulse pump at all.

I was originally going to run a pulse pump but now have plugged the hole in the carb isolator block where the nipple fitting was tapped. The boat runs great without the pump, no problems at all.

ponddipper

TY for the post JAW. I am one the those ppl who just posted asking about my iso block. My question was will my iso block work right if the tap was drilled into the center of the block's into the throat instead of drilling it into the pulse hole like you did. I got a predrilled iso block from Bonzi that wasnt tapped using the pulse hole / port. this is their repsonse FWIW:

" "Fist off, a great deal of testing has been done on the correct placement of this tap location. It has been determined that placing the pump pressure tap in the carb pulse passage will rob pressure from the carb causing low fuel pressure and possible inconsistent water pump pressure. By placing the tap in the center of the draw area, carb pump pressure is not affected and the water pump pressure is more consistent. This area has a very strong positive and negative pressure pulse that can be used with out adverse affects. " "

Whatcha think? I am going to use the iso block tomorrow and will let you know how it runs.

ponddipper

pictures...wanted to make sure you saw this...will it work?

black talon

My Feedback: (5)

i have a tapped iso block and proboat waterpump for sale on here. it came out of my blackjack 55.