Rebuilding 82' 25 HP Johnson.

[Hopper]

After investigating some silvery deposits on my sparkplug, I discovered this...<br />

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<br /><br />My fear is I will rebuild this motor and not fix the problem of why this occured in the first place. I use Chevron gas and Penziol TC-W3 synthetic blend oil and measure my mix out in a ratio cup. <br />If you have any information at to why this might have happened only to the top cylinder or any tips on rebuilding this motor, I'd really appreciate the help.<br /><br />Sorry about the long post.<br /><br />Thanks for the help,<br /><br />Hopper

 

[Backlash]

Re: Rebuilding 82' 25 HP Johnson.

Hey Hopper,<br />After the rebuild, make sure the timing is right on the money. Check your manual for both the idle timing & WOT timing specs. Looks like pre-ignition problems to me. <br />Good Luck,<br />Backlash

 

[Hopper]

Re: Rebuilding 82' 25 HP Johnson.

Thanks Backlash, I'll definately check that out!<br />Pre-ignition was my thought too.<br />One mechanic out here mentioned something called Metalization and a possible fuel delivery problem. Ever hear of that?

 

[clanton]

Re: Rebuilding 82' 25 HP Johnson.

Check upper water tube grommet, insure water tube is clear.

 

[Hopper]

Re: Rebuilding 82' 25 HP Johnson.

Thanks Clanton, is that behind or around the plate where the indicator stream feeds out of? I assume that the water tube that comes out of the impellor housing feeds into this plate somewhere to distribute the water. Or am I way off base?<br /><br />Thanks,<br />Hopper

 

[Backlash]

Re: Rebuilding 82' 25 HP Johnson.

Hey again Hopper,<br />A fuel delivery problem is another possible cause.....no fuel = no lubrication = friction = overheating. Also Clanton mentioned a possible cooling problem. All worth checking. Good Luck,<br />Backlash

 

[Hopper]

Re: Rebuilding 82' 25 HP Johnson.

Well Clanton, you were right!!!<br />I checked the upper water tube grommet and it was pinched so only 1/2 of the water could get through.<br /><br />

<br /><br />Is this pretty much all I need to look for?<br />I assume this was the problem.<br />I mean aside from making sure the timing is dead on and all carb adjustments are made when I rebuild it, should I be worried about anything else?<br /><br />Thanks so much for all your help!!!<br />Hopper

 

[norman158]

Re: Rebuilding 82' 25 HP Johnson.

you might as well give it an impeller while you have it torn down

 

[Hopper]

Re: Rebuilding 82' 25 HP Johnson.

Will definately do that Norman, thanks!!!

 

[davidd267]

Re: Rebuilding 82' 25 HP Johnson.

Does that johnson have 2 carbs?? sure looks like a lean condition as if the top main jet is plugged or some kind of fuel problem

 

[clanton]

Re: Rebuilding 82' 25 HP Johnson.

If the grommet had a groove in the center with the grommet fitting half on the tube and half off the tube, with flare on the end of tube fitting inside the groove, push the grommet on far enough to just below the flare checking fit in block and waterpump. How do you do the great photos?

 

[Hopper]

Re: Rebuilding 82' 25 HP Johnson.

Hey Blue Water,<br />It only has one carb. Not sure what it looks like behind the carb. Haven't torn into it that deep yet...<br /><br />Hey Clanton,<br />The pictures I take on my digital camera, then move them to my PC, then move them to a website. If you click on the "image" button below the Instant UBB Code you just then input the internet address to your pics and they come right in.<br /><br />Well it will be a few months before this motor takes to the water again. With ******mas just around the corner the wife might not understand me spending $300 - $500 to get my baby going again... But that gromet will be replaced!<br /><br />I sure appreciate all the help I've received here. <br /><br />Thank you all!!!<br /><br />Hopper