1986 Johnson 30 Power

[jasper60103]

Re: 1986 Johnson 30 Power

Stuck a piece of wire (stripped bread tie) through the high speed jet. It seems clear. After checking fuel pump operation lots of fuel ran out of high speed jet. A carb kit was installed last year to include new fuel lines all the way around. Carb was clean as a whistle. Head gasket was also blown last year but replaced (as far as I know based on what the tech told me). I'm happy to replace it again if it makes sense. Should I focus on the head gasket since the carb was redone and high speed jet was clear?

I would focus on getting those compression numbers closer. I would check the torque on those head bolts first. A common problem is some folks don't re-torque them after they run the motor. Check the torque and repeat the compression test. You may get lucky.

Worst case, a new head gasket is about $25 at the dealer, and it's not hard to replace. I replaced one on my '88 30hp. Just make sure your head is flat to start with. Do the figure 8 with 150 grit sand paper on a sheet of glass per the manual. Torque it to spec following the proper sequence. Run the motor and allow it to cool and re-torque it again.

 

[perwel]

Re: 1986 Johnson 30 Power

Thanks for the tip. I read somewhere to torque the head bolts to 18-20 ft/lbs starting with 10 then 15 then 20 ft/lbs. Moving from the center bolts to the top and bottom. Is this the best method?

 

[jasper60103]

Re: 1986 Johnson 30 Power

Thanks for the tip. I read somewhere to torque the head bolts to 18-20 ft/lbs starting with 10 then 15 then 20 ft/lbs. Moving from the center bolts to the top and bottom. Is this the best method?

Yep, that's sounds about right. Set torque in smaller increments (not 20 ft/lbs at once). Also, when torquing the bolts, start inside and work your way out. I have the actual bolt sequence at home. I can update you later. That's the torque value I used for sure.

 

[perwel]

Re: 1986 Johnson 30 Power

Thanks! an update wuld be great

 

[jasper60103]

Re: 1986 Johnson 30 Power

Thanks! an update wuld be great

Torque sequence:

7 -- 8
3 -- 4
2 -- 1
6 -- 5
10 -- 9

 

[perwel]

Re: 1986 Johnson 30 Power

All bolts are tight. Compression still 70 top, 100 on bottom. Going to try decarb. Then I guess the headgasket replacement?

 

[jasper60103]

Re: 1986 Johnson 30 Power

All bolts are tight. Compression still 70 top, 100 on bottom. Going to try decarb. Then I guess the headgasket replacement?

I think its worth a shot, IMO. If the decarb doesn't help, I would pull the head and inspect the cylinders before buying a new gasket. Hopefully, they're are smooth and no scoring. Else, you can decide whether you want to proceed any further with it. Please keep us posted. Thanks.

 

[perwel]

Re: 1986 Johnson 30 Power

Just decarbed. In the process the motor really bogged down as expected but never really recovered after letting it sit for 20 minutes. It would start but not accelerate without choking and dying. The water in the drum became really milky. I pulled the upper plug and the milky water was all around the plug and the plug was dripping wet. Should I still pull the head and have a look or is this a tell tale head gasket replacement issue? I had water in a cylinder last year as well and a tech replaced the head gasket. Again compressions were top 70 and bottom 100. As always, thanks for hanging in there with me on this.

 

[Daviet]

Re: 1986 Johnson 30 Power

The plug was wet with water? Pull the head gasket and see what's going on.

 

[perwel]

Re: 1986 Johnson 30 Power

Sorry. I think it was only the decarb that was dripping from the plug.

 

[perwel]

Re: 1986 Johnson 30 Power

I pulled the head and took pictures of the cylinders and gasket. Not sure how to share them but would love for someone to view and comment. Hole (1" x 1/4") in the upper left side of the gasket. The bottom of each cylinder has some groves where the piston (?) slides back and forth. The top cylinder more than the bottom. You can feel the groove with your finger but your finger nail doesn't get caught on it - best description I can give. The top piston is darker than the bottom. Is this normal wear on a 25 year old engine? This is two gaskets in two years - is there a systemic issue? Anyway, can someone help me with my next move toward fixing this. I'm happy to share photos - maybe PM?

Thanks!

 

[jasper60103]

Re: 1986 Johnson 30 Power

Hmmm, doesn't sound good. You can upload pics to photobucket (or similar) and copy the link to your posting.

 

[perwel]

Re: 1986 Johnson 30 Power

Here's the link to the cylinder and head gasket photos. Should I install the new head gasket and be done with it?

http://s1221.photobucket.com/albums/dd480/perwel/

Thanks

 

[jasper60103]

Re: 1986 Johnson 30 Power

Here's the link to the cylinder and head gasket photos. Should I install the new head gasket and be done with it?

http://s1221.photobucket.com/albums/dd480/perwel/

Thanks

Yea, I suppose its worth a shot. It's strange the head gasket was replaced once before and yet it has a big hole it?
edit: Have you noticed any cooling problems? Pumping good water? Make sure the head is not warped.

 

[AlTn]

Re: 1986 Johnson 30 Power

use a straight edge and holding the head at eye level move the straight edge across the head lenghtwise, down each side, and angled across the head. If you can see light between the head and the straightedge at any point, the head needs to be surfaced using the sandpaper on glass/figure 8 method. Your head may be "dipped" in the area that the head gasket is blown.

 

[perwel]

Re: 1986 Johnson 30 Power

Thanks guys. No cooling problem that I can see. Steady stream **** and water spitting out the back of the shaft beneath the head. I'll check for dips or warping before reinstalling new gasket.

Thanks again.

 

[perwel]

Re: 1986 Johnson 30 Power

Installed the new head gasket last night. Engine started right up, low speed adjustments are working and the cooling pisser is stronger than ever. Thanks for everyone's help with the diagnosis and repair. I sure learned a lot and have acquired some cool new tools for next time. Hopefully next time is a ways off!

 

[AlTn]

Re: 1986 Johnson 30 Power

don't forget to retorque the head and do another compression test to use for future reference