1958 Johnson 18 Sea Horse FD12 not moving water

[Boatdrinks]

Hey guys…another old Johnson Sea Horse question…( I just love the old iron). Engine in question is a 1958 Johnson 18 Sea Horse FD12. I recently acquired the engine and it’s in solid mechanical shape. I went through the entire engine…pulled the flywheel (found new points and coils there), pulled the head, pulled the exhaust manifold, pulled the lower unit, etc. The problem I am having is I can’t move water. The engine runs like a top…had good compression, new water pump, etc… But she won’t move water. I had a leaking head gasket on a previous engine that caused it to not move water so that is why I pulled the head off. Everything looked good…replaced the head gasket and still can’t get any water moving. The impellor is new…the water tube grommets are new….everything is put back together correctly. I have had the lower unit on and off several times…you gotta love lining everything up doing that… But I just can’t seem to get the engine to move water. The water pump looks good….pin in place on drive shaft…backing plate…new impellor. It’s got me stumped. I haven’t been able to find any clogged passages in the waterways…as a matter of fact, the waterways in the engine head and exhaust manifold area were remarkably clean. It was moving water before I took the lower unit off….I had water in the oil…so I had to reseal the lower unit. I am totally baffled here…I have checked and rechecked everything several times. I have even ran the engine without the lower unit on (garden hose to water tube on engine). She’ll run all day like that…but she does get warm below the exhaust manifold. A sign perhaps? I am at my wit’s end here guys…. So I set her aside before I use her as an anchor and am asking for help here. Anybody? Thanks in advance….

 

[Chinewalker]

Re: 1958 Johnson 18 Sea Horse FD12 not moving water

Hi BoatDrinks,<br /> Couple of things to check. If you're running in a bucket, the water level should be up near or above the bulge where the waterpump is located. They don't draw well if it's drawing from down low to start. <br /> Second, if the waterpump housing or base plate is warped at all, or if the sealing surface under the base plate isn't clean and free of corrosion, missing chunks, etc. then it'll suck air instead of water.<br /> It is possible to localize the issue running the gearcase off a large drill, to see if the pump itself is working. Not a good idea if you tend to drop things easily (electric drill and a bucket of water - not good if they mix!!) A cordless drill with a 1/2" chuck might do it best...<br /><br />- Scott

 

[MCM]

Re: 1958 Johnson 18 Sea Horse FD12 not moving water

Has it got a t'stat, if so replace it. Also I'm not sure having water in the L/U oil has anything to do with the motor moving water, as you said the you had to re seal it

 

[Chinewalker]

Re: 1958 Johnson 18 Sea Horse FD12 not moving water

No T-stat on a 1958. First year for those was '59...<br />- Scott

 

[MCM]

Re: 1958 Johnson 18 Sea Horse FD12 not moving water

Guess that leaves that out

 

[Boatdrinks]

Re: 1958 Johnson 18 Sea Horse FD12 not moving water

I hadn't thought of the power drill trick...I will have to try that one. I have ran the engine on the muffs and in a bucket to no avail... I did have some machine work done to the lower unit where the water pump screws were (they broke off). I had the old screws drilled out. They had to reweld in the holes and re drill and tap. I gave them the water pump housing and backing to use as a template. It looks like they got it back in the right place...I have nothing but memory to make a reference to. Another question I had was...I am using 8/32" screws on the water pump housing now. They are just a bit smaller in diameter than the original bolts were. They are a little too small in diameter for the water pump housing...but I didn't think that would be an issue. I put flat washers on the screws and tightened them up. Could this be the problem? I mean, nothing is sloppy and the water pump is solidly screwed in place...but I have been thinking about what the #$!##@$ could have happened to change things... Thanks a lot for the tips guys...keep 'em coming! I will try the drill in the bucket trick before I disassemble the water pump and let you know...and if that doesn't wo

 

[Boatdrinks]

Re: 1958 Johnson 18 Sea Horse FD12 not moving water

Hey guys...I got her moving water good! Here's what happened... When I got the bolt holes for the water pump repaired, the machinist damaged the area just below the water pump plate. The pump was sucking air... So I filled in the damaged area with some JB weld, filed it smooth and she pumps water like there is no tomorrow! Thanks for all the help guys...