jdoug

When I first put my boat in and ran it...it was shooting a stream about 3 ft. out the outlet. I thought cool, I have excellent flow through my cooling system. I was having a little trouble getting my engine to run really well. Then I thought about it...what if my engine has not had the chance to warm up to normal operating temperature? I lifted my water pickup a little and cut down a little on flow...this helped! The engine ran much better after that. I guess I was cooling the engine to much and not letting the engine actually warm up to where it needed to be. I've seen boats in pictures that are just flying with these highly modded race engines and just seeing the water kind of spitting out the outlet not streaming. I figure these guys know what they are doing and aren't burning up their engines.

How do you know how much water to flow through the cooling system? Experiment as I did?

xxxboatworks

What kind of engine? Water cooled tuned pipe? You always have the option of letting your boat run for 30-45 seconds on land before tossing it in the water to get the engine up to operating temp.

jdoug

I run a 25cc Homelite w/tuned dry pipe and wa257 carb.

BMoneySL

I warm up my engine for about 1 Min then throw it in the water. And I dont get on plane for about 3-4 mintues just so I know its really warmed up.

skoda450

My experience is that you can cool the Homelites too much. They are designed to run with only air cooling. The water jackets can cool them down to the point of not running well at all, especially if you have opened up the intake with a big bore carb like the WA257. Think of starting a weedwhacker. It' s cold so you need to choke it, right? Once it warms up, you need to take the choke off or it won't continue to run, where it wouldn't run or start without the choke before. This situation is magnified when you add a larger bore carb. The engine is then taking is more air and therefore already running cooler than designed. If you add water cooling to the mix it all gets worse. Water cooling is great but it must be done in the proper amount to get the engine back to it's proper operating temp. Limit the water flow by constricting the EXIT hose some how. I have used smaller inside diameter tubing, valves (both bought and home made) and just partially pinching off the tubing. The valve works best in that you can more precisely control the restriction. The best is a home made version that is made from a 1/8" plastic tee from the auto parts store windshield washer tubing parts section. The water is passed through with a 4/40 screw in the stem of the "T" partially blocking the flow. Adjust the screw in/out for the flow you need.

jdoug

That too, is what I found. I was cooling my Homelite too much. I have the pick up in the prop blast above the water line. I can adjust the amount of water flow by pulling my pickup up out of the way. The higher I go with it, the less water I get through the system. Last summer I mostly ran at the reservoir that's near my house. It's pretty good size but only about 80 ft. deep at the deepest. It gets really warm. I can run alot more water through the system there than I can when I stay in Chelan, Wa. because Chelan is a 1500 ft. lake that fills with runoff every year. It's a lot colder, so in order for my boat to run right in colder water is to decrease water flow. Makes sense to me. I just haven't heard of people talking about this.

Do the water temps have as much effect on the Zens as they do on a Homelite?

Jeremy.

lzvagias

i'm curious about the tunning of your carbs. i have to repectfully disagree, i used to run my 25cc homie that i water cooled with no symptons of running too cool. i can only speak for myself on this and what i have experienced and i'm no expert! if i ran it for a minute out of the water it would began to wind up (lean out). i definetly would have melted exhaust orings. but in the water it ran great. it wouldn't take very long to get to temp and i ran tube in prop wash and used a pump. are you sure your not running too rich causing it to run poorly until it heats up and leans out a bit? try leaning it out a tad and see what happens. you guys could be right and maybe i have just been lucky with my homie and zen.

Justaddwata

My Feedback: (3)

Whats the current pond temperature. Chances are that if it is cold (near freezing) then you were running a little cool. I would recommend moving the pick up as the weather warms or you may have issues of being a little too warm.

A common method of warming the motor a little with a water cooled manifold is to pass cooling water first through the manifold before entering the cooling head. This will preheat the water into the head. Again - these are considerations for COLD water running only !!

skoda450

Yes, routing the water through the manifold first would preheat it but it would also greatly reduce the flow rate and accomplish the same thing as I suggested earlier. My experience has been with changing to the Walbro barrel carbs (WYK?)that caused the problem I spoke of. They have no mixture adjustments so you get what you get as far as mixture is concerened. They are very simple and give a very clean path to the intake and better performance. But I have encountered this poor performance problem after the motor is in the water a few laps. Keeping the engine temp up eliminates the stalling.