Water issues Johnson 10HP

[sbump26]

QD-16 10hp Johnson. Removed lower unit, blew air through the pee hole, felt little air come out tube inside shaft. Blew air through tube inside shaft, felt little air out pee hole. Used one gallon pressure sprayer and sprayed water up water hole in shaft. Water came out pee hole. Did vice-versa, water came out. Put lower unit on, made sure water tube inserted into shaft, started motor in trashcan. No water from pee hole in back of motor. Impeller looks new. Vanes soft and pliable. Did notice that no gasket sealant was used any where on unit. Just three screws holding housing to lower unit. Any ideas? Did not run too long, about 2 min.

 

[Paul Moir]

Re: Water issues Johnson 10HP

QD-10 - 1949/1950 10hp engine.<br />Just a thought - are you sure the impeller key is still in place? I mean, are you sure the impeller turn when the driveshaft does?<br />There's no sealant used on that pump, except under the wear plate. Even if it had none, it should still pump. Oh - the pump must be submerged (at low speeds) for it to pump anything.<br />It's standard practice to replace the impeller when ever its out, and as often as once a year. You can get a new one from any Johnson/Evinrude dealer, or Napa autoparts, or many online places.<br /><br />Hope this helps!<br /><br />PS - did it overheat after the 2 minutes of running?

 

[sbump26]

Re: Water issues Johnson 10HP

Yes the key is in the impellar. I wonder if I should put the boat in the water and try it. I also wonder if the impellar vanes were facing the right direction. I just got the motor and know nothing about its history. It didn't get too hot. I could still touch the head for a second. There is no sealand even under the metal plate the impellar is on top of.

 

[Paul Moir]

Re: Water issues Johnson 10HP

Things may be normal. I just reread your post - these old engines don't have a telltale like a modern engine. Instead, all the cooling water goes out with the exhaust. You should get a spritzing mist out of the idle exhaust relief port though - the hole on the leg.<br />If the engine never gets too hot to put your hand on and count to five, it's not overheating.<br /><br />EDIT - if the impeller was installed backwards, it would turn the right way round when you cranked the engine. Don't sweat it.

 

[wayne h]

Re: Water issues Johnson 10HP

if its like my 9.5 you have to warm it up when the thrmostat opens you will see more water comming out run it and see what happends.if you can hold your hand on the head for 3-4 seconds without getting burned then its getting water. there is no gaskets in that waterpump so dont worry about that.and its hard to tell a good waterpump impeller from a bad 1. it sould be changed 1ns a season in saltwater and everyother season in fresh. they are cheap its not worth waisting and engine for a 15 buck impeller.

 

[Solittle]

Re: Water issues Johnson 10HP

When you remove the lower unit to replace the impeller, remove the thermostat cover if you have one and backflush with a hose through the water pickup tube - then new thermostat.

 

[Paul Moir]

Re: Water issues Johnson 10HP

No thermostat in this engine Solittle and wayne. That didn't come till '57 I think.

 

[sbump26]

Re: Water issues Johnson 10HP

I don't think it has a thermostat. it has a hole on the back of the shaft and another on the right side about mid way up as you look at the motor. it had a little bit of oil coming out this hole. It gets pretty hot, not like you can put your hand on the head and leave there very long, a second max.

 

[Paul Moir]

Re: Water issues Johnson 10HP

The head normally should run pretty hot. It doesn't have a lot of water passages. Try holding your hand on the top of the block, just over the top cylinder. If its getting too hot there then you know its overheating. Any signs of steam would be a sign too. <br />There is no thermostat in that engine. They didn't bother with them until the late 50's, and then only on the larger engines. I don't think the 4hp engine got one until the 80's.<br />Replace that impeller anyway. Repair kit 18-3203 from Napa, out of their marine catalog.

 

[OBJ]

Re: Water issues Johnson 10HP

Outside shot here...sbump, was there enough water in the trash can to cover the lower unit well above the mating line between the lower unit and midsection? Outboard water pumps do not draft water. They have to be submerged in order to operate.<br /><br />Good Luck.

 

[rolmops]

Re: Water issues Johnson 10HP

Hello.<br />Did you turn the driveshaft clockwise when you seated the impeller and while you tightened the screws? Did you check the water passages below the impeller?<br />The QD16 is a 1955 and has no thermostat<br />Good luck.

 

[R.Johnson]

Re: Water issues Johnson 10HP

These little engines run pretty cool to the touch, and should throw a healthy stream out the exhaust reief hole. On these engines I deburr the water tube on both ends so that it won't snag, or roll the rubber grommet. On an engine this old, replace the upper grommet. Seal down the empeller plate. A leaky head gasket, or exhaust cover gasket will also effect water flow, very possible on an engine this age. As stated earlier, make sure you have water over the pump when testing.