Water pump

[mrford]

Hi nuby to seagulls just got the nicest most beautiful 40 plus SJP 301 M4 put it in water 2 pulls and it runs well !!! No water at the tell tail . I put the hose on the tell tail hole to back flush no help took it out of the water out the hose on the intake of the pump and water came out of the drive tube holes . So i took off the lower unit I think the copper tube was in the hole but not 100 % sure . The impeller is 3/16 s shorter than the housing . I don't like this am tempted to make one taller leaving some room maybe 1 /32 inch than 3 /16 inch . I blew air up the copper tube and it came out the tell tail and when I plugged the hole it held pressure . Its to simple not to fix my friend said take off the prop may be it was not deep enough I had water only to the gasket line on the lower unit guess the impeller was out of the water ??? You guys know best what do you think ??? Vic Thanks HELP

[david1230]

Welcome to the forum!
Try it again in the test tank with 2 inches OVER the bottom of the exhaust tube.

[1650bullet]

The exhaust tube is the alloy or polished tube that should have one screw that mounts to the bottom of the engine block. The copper water tube that is inside of the exhaust tube mounts into the hole on the exhaust housing. The water line has to be 2 inches above the bottom of the exhaust tube that just slides over the exhaust sleeve on the gearcase. As for the water pump. They are a hard plastic and nothing like a OMC--Merc--Yamaha--Tohatsu outboard impeller. Here is a pic of a cutaway of the waterpump housing from the web-site. As you can see there is heaps of space between the blades of the impeller and the housing. Water will only pump as you turn the revs up. If you idle the motor it wont pump. Thats how they were designed. I think this is the answer you might be looking for.

[bychance]

Even though I've had this cutaway picture for a while, I just noticed that maybe the copper water pick up tube is sitting in the wrong spot.

It seems to be dangling in the exhaust outlet and I think it should be in the next small hole in the housing toward the impellor?

[mrford]

Well you were spot on I needed more water in the barrel . The speed and angle make a difference . Is it 2 inches above the steel tube or just above the flat spot on the aluminum housing ??? Well my baby runes pumps water and makes smoke thats how life should be . I am using ames synthetic oil os this O K or should I NOT use this ??? Thanks for the help Happy VIC

[david1230]

Great to hear it...you can also push an aquarium tube connector inside the water outlet and have about 8 inches tubing hanging down from it (but not touching the hot exhaust of course). This really gets the water pumping due to atmospheric pressure. I used this a couple of times, but because the flow is immediate and never stops even on slow idle, the engine never gets even warm.

The Seagull engineers knew best and that's why unless the passages are blocked in the motor jacket or elsewhere, its quite normal that water takes a short while before spewing out the outlet. But the engine has to rev faster than idle of course and if not, it should only be run no more than a minute or the engine will get quite hot and may even seize.

The specs say 2 inches water level above the gearcase plate, but I find that 2 inches above the exhaust bottom tube end assures a better flow. (like you discovered yourself). Anyways, when you're in a boat, the exhaust tube is usually quite low in the water...unless you're sitting midship with your belly forward
I have no experience with synthetic oil but I'm sure another forum member can give you the full story on that.

Happy trails Mate...I mean oily water trails of course

David
Ottawa Canada

[mrford]

Boy I like the hose out the tell tale like a syphon I guess I may have to try this as I like to run slowly maybe a copper tube ??? Well thanks for the Information and I will make lots of blue smoke !!! Its amazing how rudimentary these machines can be and my seagull sat for 4 years that I know of and started second pull !!! lets see a merk or johnson do that !!! My dads Scott at water would do that it was built like a 2 cylinder seagull with a cover and it was from the early 50s and still runs today . I love my seagull and my model A ford Thanks happy VIC

[david1230]

Yeah...we had a Scott Atwater 7.5hp when I was young and my dad had built a light-framed 8 foot speedboat out of canvas covered with shellac.
That thing could reach 30 mph and was the fastest boat on the river at that time. Also had a brass racing prop.
The engine was quite reliable, and had an automatic "Bail-O-Matic" pump that you hooked a hose to in order to bail out all the water in the boat. Never seen that on any motor since
He almost started a franchise in the city where we lived, but Scott Atwater started having financial problems and we didn't want to get our feet wet with a losing company.
Wish I had taken some pics of the setup in those days...

No GPS in the 50's to mark the speed...my dad ran the '48 Oldsmobile parallel to me going full speed on the canal next to the road he was on. Just as excited as I was, he almost crashed the car in a tree along the riverbank when he looked at the speedometer! That would have been a sight!

[mrford]

WOW that so cool how fast did you go ??? Think auto baling and who dropped the ball ??? Old stuff rules !!! And you did not have to remember a phone book full of stuff just to start it up !!! The simple things what pleasure . Thanks for a good story Happy VIC