dad gummit - '70 25 hp

[reka12]

Ok, son and I went to the store and got two sets of plugs, autolite and champion. The only reason for the autolite was to get the equivalent temp range. Put the autolites in first since they were the cooler. Started great but immediately quit firing on the top cylinder. Took plugs out and noticed the tip was squished down to the electrode. Thinking that it may have been the wrong size plug, put the champions in. Ran great. Took out plug and noticed the bottom was too hot. I inspected the autolite plugs and noticed a few nicks. Took the head off and sure enough, there was a small piece of aluminum and the piston and heads were nicked. Cylinders seemed ok.<br /><br />I broke one of the had bolts off the first head gasket change and worked mighty hard to get if off. I do not think I broke any of the case. I stuffed rags in the cylinders while cleaning it up and blew wd40 prior to reassembly.<br /><br />Well, i took the dremel and a wire brush and smoothed down the nicks. They do not look too deep and put it back together. I know the part is aluminum and looks like a pointed end to something. Of course it has been smoothed a bit.<br /><br />What do you guys think? I have not run it yet. Any ideas of what it was? Does this motor have a chance without a new piston and head?<br /><br />Your thoughts please. Thanks. Mike

 

[DHPMARINE]

Re: dad gummit - '70 25 hp

I have to start by saying I've never seen autolite's do a Johnson any good.<br /><br />A picture would really help,here.Do you think the nicks were from the plug electrode ? or were there a whole bunch of nicks ?<br /><br />Try a compression test next.<br /><br />DHP

 

[reka12]

Re: dad gummit - '70 25 hp

No, there was definately a small piece of metal in the cylinder. It banged around inside quite a bit. I could tell it was not a piece of the spark plug or a ring. It is definately aluminum.

 

[what66]

Re: dad gummit - '70 25 hp

well I'm no expert but if the cyclder looks ok and<br />the piston is intact it should be ok. <br />I would say put the head back on and do a compression test if all seams ok I would think it will be ok.<br />do you think that pic of metal that was in there was from the piston?

 

[reka12]

Re: dad gummit - '70 25 hp

Well, looks like no harm done. She's purring like a kitten and idleing well. I am not sure what it was, it was not from the piston. Although we were careful putting it back together, it ust have fallen out from a water guide, got stuck to the gasket when putting it back together or who knows. Felt like a real shadetree when I saw it in there. Hey, I resemble that remark...

 

[Lkoschak]

Re: dad gummit - '70 25 hp

What number Champion spark plug did you use? <br />I never heard of an autolight subsitute.<br />I think the champion should be something like a J4J.

 

[reka12]

Re: dad gummit - '70 25 hp

J4J is what is called for in the manual but have not been able to find them. Paul Moir suggested J6C but I have not been able to find them either. I am running J8Cs now. I am going to lake test tomorrow to see what they look like. Interestingly enough, the champion book at Ace hardware indicated that the J8Cs were the called for Champion plug for this particular engine.<br /><br />I got the autolight 303 from Advance. That's what here book said. They are now in the trash can.

 

[Paul Moir]

Re: dad gummit - '70 25 hp

They shouldn't be very hard to find. I get them at my local Canadian Tire, but I take it that's no help to you folks. I expect you'll find the J8Cs too hot - that Champion book is simply wrong.<br />The difference between the JnJ and the JnC plugs is the design of the ground electrode. There is no significant difference, other than the JnJ plugs are no longer made.<br /><br />There's a nice current J/E spark plug chart right here:<br />Click here.<br /><br />I'm glad to here that the engine seems fine for it's troubles. I wonder if the chunk came in from the exhaust or intake rather than having been left behind when you had it apart? Seems more likely to me.

 

[reka12]

Re: dad gummit - '70 25 hp

As much as it pains me, I tend to believe that I left it behind. Thanks for the chart. It is helpful. Also, thanks for your help! I popped a cold one tonight (would have been a Molson would I have had one in the fridge) to celebrate. I am sure that other's have felt that satisfying experience when you finally get an old motor to run new again. It is also fun to chat with those who get into the experience like me. Most of the week I am with some very intelligent scientists and engineers that don't know the difference between and outboard and inboard so its no fun to share the experience. Mike

 

[R.Johnson]

Re: dad gummit - '70 25 hp

I don't like to say this! but that chunk of aluninum came from somewhere. I would take off the exhaust cover, and take a look at the piston skirts.

 

[reka12]

Re: dad gummit - '70 25 hp

I'll take your advice. I have a gasket set on order and I'll do it then.

 

[reka12]

Re: dad gummit - '70 25 hp

Saga continues...I cleaned up the motor and we ran it for 20 minutes or so on the lake. The top cylinder quit firing again. I took the head off and sure enough, there is a small (1/8" long), flat piece of metal (magnetic) that has been driven into the head like a knife. I went ahead and removed the exhaust cover (no small feat) and the upper bypass cover. What I could see of the rings looked ok. This time however there is a noticible scratch on the top of the cylinder. You can feel it with your fingernail.<br /><br />I put everything back together, new gaskets and all and now the compression reads 95 psi top and 125 psi bottom. Not good right?<br /><br />The thing I don't get is I clean up the top of the piston and the cylinder head, put a new plug in and the motor runs fine, for a while. I just return from the lake and once more the spark plug electrode has been beaten down flat. There must be something else in the cylinder. I have not removed the head as I am out of gaskets.<br /><br />Anyone have a guess as to how much this motor maybe worth parting it out?

 

[Docdoc]

Re: dad gummit - '70 25 hp

Retail for that motor is probably $250-$300. E-mail me. I may be able to use the lower unit if it will fit a 69 25 HP Seahorse.<br />Jerry<br />jkjmtaj7@cox-internet.com

 

[reka12]

Re: dad gummit - '70 25 hp

Doc: When I get back in about a week, I will send you an email. I have the parts catalog for this motor so we can trade notes to see if it will fit. The lower unit is in good shape.

 

[reka12]

Re: dad gummit - '70 25 hp

Doc: You still need the lower unit?