1960 Johnson 40hp Sea Horse

[FishMagnet]

I finally got my boat out in the lake, and it ran better before I changed the impeller. Not sure if I messed something up in the process.<br /><br />First off, should I get a "pee" stream immediately or after it warms up a bit?<br /><br />Second it now goes in reverse (very slowly) whether its in forward, neutral or reverse.<br /><br />I did have a stream before I changed the impeller, but it did run awhile first. I was a little afraid this weekend and didn't let it run long. <br /><br />Matt

 

[Laddies]

Re: 1960 Johnson 40hp Sea Horse

that engines only tell tale is at the exhaust bypass when the termostat opens sounds like the shift linkage is not hooked up right better re ck

 

[Paul Moir]

Re: 1960 Johnson 40hp Sea Horse

It should only start 'spraying' after the engine warms up a bit. Water is recirculated through the second tube into the pump until it heats up; then it gets dumped out through the hole in the back of the engine.<br />To see if you have good water flow, remove the thermostat and run the engine without the thermostat cover on. If you get a good geyser from it, you're good to go.<br /><br />As for the shift problem, it sounds like you didn't get the shift rod back into the coupler properly. Remove the window and observe it while shifting and turning the prop a bit.

 

[FishMagnet]

Re: 1960 Johnson 40hp Sea Horse

Paul, here's where I'm at.<br /><br />I pulled the thermostat out and tested it with a meat thermometer. It opened at around 160 degrees give or take a few. I left it out and started the motor. No geyser. I dropped the lower unit out again and checked the impeller, the new one I put in had chunks broken off of it. I still had the old one which is in good condition and put that in. Started up the motor again. Still no geyser, not even a drop coming out of the t-stat "hole".<br /><br />As for the shift rod, what is the best way to get it connected properly? I pushed it down so the lower unit was in reverse, then shifted from my console into reverse and connected them.<br /><br />Thanks in advance,<br /><br />Matt

 

[FishMagnet]

Re: 1960 Johnson 40hp Sea Horse

While I'm thinking about it. Should I be able to turn the driveshaft by hand with the impeller in and housing screwed down? The impeller and housing is VERY snug. I hope I didn't shred the old one.<br /><br />Matt

 

[Paul Moir]

Re: 1960 Johnson 40hp Sea Horse

If you didn't lubricate the impeller at all, the driveshaft will be difficult to turn by hand. Did you replace the housing as well as the impeller? What were the P/Ns?<br />Another idea - did you test with water up to the lower unit seam? That is to say, was the pump submerged?<br /><br />I connect the coupler by reaching in through the window with needle nose pliers, grabbing the lower shift rod. Then I manipulate the upper rod & connector with the shift handle. The bolt must go in so it keys into the grooved part of the shift shaft otherwise it'll fall out. Before putting the bolt in the coupler, I check with a flashlight to make sure it's all the way in. Careful not to torque those bolts down too hard or the brass coupler will strip out.

 

[FishMagnet]

Re: 1960 Johnson 40hp Sea Horse

I did not change the housing too, just the impeller. The water comes just barely over the seam in my barrel. Unfortunately when I fire the motor up it kicks a few inches of water out. If the barrel was any taller though it would hit the tilt/mounting portion of the motor.<br /><br />Is there any certain gear I should try to reconnect the shift rod in, or does it matter? I'm hoping thats it because it did shift properly before I replaced the impeller.<br /><br />Thanks again,<br /><br />Matt

 

[Paul Moir]

Re: 1960 Johnson 40hp Sea Horse

No, there's no adjustment to be made at the shift rod connector. You either get it in correctly, or you don't.<br /><br />That's very mysterious about the new impeller coming apart. If you can get the impeller P/N please post it and I'll double check it.

 

[FishMagnet]

Re: 1960 Johnson 40hp Sea Horse

18-3083 is the number I have in front of me. Does that sound like the correct p/n to you? The new one I put in started breaking off at the tip of the vanes.<br /><br />Looks like some nasty weather coming my way so it may be a day or so before I get a chance to work on it.<br /><br />When I took the t-stat out I noticed underneath it is a spring with a "cork" on top of it. Can I ask, what is the function of this? It justs sits in there and sure doesn't seem like it would do much. <br /><br />Thanks again,<br /><br />Matt

 

[FishMagnet]

Re: 1960 Johnson 40hp Sea Horse

Paul, I appreciate all your help. I haven't had any luck finding a mechanic that works on the older motors nearby so I'm glad you're here.<br /><br />With the thermostat off, at idle speed, I am now getting a bubbling brook. No geyser, but water is now coming out.<br /><br />Matt

 

[Paul Moir]

Re: 1960 Johnson 40hp Sea Horse

Bubbling brook sounds good for idle speeds. I checked that P/N, and a few other things. As far as I can tell, it's absolutely correct. BRP has superceeded the impeller number from 377230 to 777213, but they havn't changed the housing p/n so I don't think there's been any water pump redesign (they've done this with some other o/bs). I also don't think that there's any other (incorrect) water pump that would fit on your 40hp, especially due to the 2-line setup yours has.<br />I take it you didn't notice any differences between the Sierra impeller and the old one?<br /><br />As for the thermostat - the dooey with the spring is supposed to allow the entire thermostat to be 'pushed down' when water pressure builds up. The idea is that at higer rpms the thermostat alone doesn't allow enough water though it to cool the engine. So the pressure from the water pump pushes the thermostat down, allowing extra cooling water to bypass around it and out the drain. <br />Hope that explains it!

 

[FishMagnet]

Re: 1960 Johnson 40hp Sea Horse

Thanks again Paul. I am now waiting for my new thermostat to arrive, so I think I will wait on going any further until I receive it.<br /><br />The shift rod is solidly connected so hopefully by the weekend I'll be able to give it a test run out in the lake.<br /><br />Matt

 

[FishMagnet]

Re: 1960 Johnson 40hp Sea Horse

I had a little bit of time to work on the motor today, and guess what. Not even a drop of water out of the t-stat hole. I didn't have a chance to drop the lower unit out, but my only guess is the impeller broke again. I had read before it didn't matter whether you lubed the impeller or not. Is this true? The only thing I can think to do would be to lube it a little and hope it moves easier and not break.<br /><br />Matt

 

[Paul Moir]

Re: 1960 Johnson 40hp Sea Horse

I think the problem has got to be insufficeint water in the barrel. Really, I can't imagine anything else. Impellers don't disintegrate for no reason, and if they're not operated without water they're quite durable. <br />You can lube the impeller with soap to ease assembly if you wish. But the impeller doesn't need it to function - once it washes out, it's gone.<br /><br />One thought - if you do pull the l/u again, go over the water intake system with a fine-toothed comb. I belive on your o/b the water intake for the pump comes up a cavity beneath the impeller. This cavity shares a wall with the exhaust - make sure that wall is intact. I rather doubt this is the problem, but it's worth checking if the L/U is off.<br /><br /><br />Good luck!<br /><br />EDIT: Another idea - check the entire intake for obstructions. The water travels up from the intake behind the prop, across the l/u behind the long, thin plate just above the cav plate, and up to the pump through that cavity underneath it. Was any peices of the old impeller 'missing'?

 

[FishMagnet]

Re: 1960 Johnson 40hp Sea Horse

I think I've got it figured out. There indeed was a bunch of gunk throughout the intake. I hope I've got most of it flushed out. Using a hose water flows through easily now.<br /><br />One more question and I'll leave you alone. <br /><br />Underneath the impeller housing is a thin metal plate which the impeller rests on. My pump has two pipes coming out of it, this metal plate covers one hole and has an opening to allow water through the other one. Which hole gets covered?<br /><br />Matt

 

[Paul Moir]

Re: 1960 Johnson 40hp Sea Horse

Glad you found the problem! The intake should be entirely screened off to prevent this - is the screen or the core plug at the end of the fin missing? <br />The thin metal plate ('wear plate') should be installed so the large hole on the edge is toward the port side of the engine. I guess that makes it below the water return tube. I use sealer between the wear plate and the lower unit, though others don't and have success too.<br />The entire pump is replaceable with OMC 379775 if your housing is worn. ~60-$70.<br />Hope all that helps!

 

[FishMagnet]

Re: 1960 Johnson 40hp Sea Horse

I'm proud to say I had the boat out on the lake today and she ran like a champ. Well, at least until my new steering cables came loose. That made for a fun time.<br /><br />Thanks for all your help.<br /><br />Matt

 

[tjh408]

Re: 1960 Johnson 40hp Sea Horse

I have a question for you guys. How do I drop the lower unit on my 1960 40 Lark. I removed all the bolts, still hanging, like there is a bolt in the rear over the water intake. Also do I remove the bolts in the shift coupler?<br /><br />Thanks

 

[Paul Moir]

Re: 1960 Johnson 40hp Sea Horse

Welcome to Iboats, tjh408! You should start your own topic with a nice, descriptive title and indicate what type of 40hp Lark you have - the electric shifting one or the manual shifting one. <br />I will tell you now though that to remove the l/u from those 40hp engines there is a large bolt that holds the l/u on from above in the back, and you need to remove the entire back half of the exhaust housing to acess it. There's a pile of bolts to remove to do that.<br />Also, if it's a mechanical shift, you disconnect the shift linkage behind the acess panel on the starboard side of the mid-section. You must completely remove one of the bolts.<br />No need to bother replying to me here though; start that new post if you need to.