Johnson Seahorse Jw-15 Need Help!!

[Freshfish00]

I just recently bought a 1959 3 hp motor and I rebuilt the carburetor because it wouldn't stay running for more than 1 minute tops. I did some work on it and got it to run good for a long time, went threw a half tank of gas testing and running it, verified idled was good and fast speed was good also. No here is the problem I had... it got extremely hot started to smoke and eventually quit, i also noticed that the 4 little holes on the shaft didn't have water coming out any longer but smoke instead. Also the back side of the shaft (lower portion of motor that has the prop attached) is now covered in oil. Did I just ruin this motor or is it fixable? Did the water pump burn up? Any help would be appreciated. .....

 

[dkonrai]

yes change that impeller. sounds like the impeller went bad.

 

[dkonrai]

yes change that impeller. sounds like the impeller went bad.

 

[racerone]

A " new to you " motor must always have a new impeller installed.----Most motors are ruined by folks who do not know the basics.

 

[F_R]

You asked if you ruined the motor. Well since you ran it so hot that it seized and quit, probably. At the least, you severely damaged it. For certain it needs a water pump, and you have burned the head gasket so that needs to be replaced too. While you are at it, remove the flat plate from the side of the cylinder block, and you will be able to see the sides of the pistons. If they are scuffed, well that is bad news.

 

[racerone]

edit

 

[Freshfish00]

Do you think it is seized up if i can still pull the starter rope with ease? It ran for about 1minute before it quit. Should i replace the water pump ans see what happens or is it too late?

 

[Xcusme]

Look,....here's the deal....you don't know until you LOOK at it...If what you are saying , about 'running a minute before it quit..." is true...then you may have been lucky and not too much went wrong. Now the good news, after you replace the water pump and the cylinders "look" ok , and you start it, it just may be ok. Do a compression test and see what was done. Perhaps the former owner didn't run it with a bad pump and you get lucky. But you have to do your part. Get a water pump, install same...do a search here and find out the RIGHT way of installing it. Get a new head gasket, again , read here about the right way ( get a flat surface to mount it on) to install same. Then give her a start up and report back. For a good note, they made those engines, in the 50's right, they are tough, and they take abuse , up to a point.
F_R is a very well known guy and you should do as he says. He tells it as he see 'um, ...I hope you have good luck.

 

[Freshfish00]

Ok, I tore motor completely apart and replaced headgasket, exhast gasket, impeller and spark plugs and replaced the starter rope. I am trying to start it right now and no luck. I have #30 of compression in the upper cylinder and only #10 in the lower cylinder. I have good spark and fuel, so what happened to my compression? I took the head back off to look at the pistons and i see no visible problems. Any ideas?

 

[pn]

well hindsight is 20 20, i would've done a compression check before going throught all the trouble changing out parts. terrible

 

[nwcove]

that doesnt sound promising. did you "lap" the head before you reinstalled it with the proper torque and bolt pattern sequence?

 

[Freshfish00]

What is "lap"? I lightly sanded it down flush and yes i torqued all the bolts to specs (no more than 84 inch pounds is what i found out online) I used a torque wrench to do this. When it got hot and smoked like i stated in my earlier post, could it of blown the rings?

 

[nwcove]

"lap" is what you did by making the head perfectly flat. were the pistons scored when you had a look through the ports with the exhaust cover removed? how did the cyl walls look when you had the head off? the prognosis probably isnt good.

 

[Freshfish00]

Cylinder walls are cracked! I can feel a "hang-up" with my fingernail and see it now, well that stinks..

 

[Freshfish00]

Do you think a thin coating of jb weld and then sanded down would hold up? Says it withstands temps up to 550

 

[Freshfish00]

Will any other powerheads work from a different year motor or does it have to be a 1959 head? I really need help on this. I took it apart to check the cylinder wall once more, put it back together and now I have no compression where as before I was getting about #30 on the top and #10 on the bottom. What happened?

 

[HighTrim]

No way sorry, that powerhead is scrap.

Good news is that you should be able to find a good replacement, for not too much cash. Post a wanted ad at aomci.org in the webvertize.