Experts' what would you do next? 15 Jonny

[kodibass]

Driving me nuts, This Jonny mod# J15REOD SN#G 03758787 It starts ok, once warm will not idle, and very very hard to restart. adjusting the low speed screw seems to have little effect, compression top-75 bottom 85 I rebuilt the old carb no better so owner says buy a new carb $293.00 new carb no better.. changed fuel pump from running motor, spark will jump 7/16 gap napa spark tester on both cylinders...I changed out coil unit and power pack from a parts motor just in case, no better... where should I go next with this thing?....other than the deepest part of the north pacific! help!!!!!

 

[Rick.]

Re: Experts' what would you do next? 15 Jonny

That sucks about the new carb. Have you done a linc and scyn after having the carb. off? Best of luck. Rick.

 

[BonairII]

Re: Experts' what would you do next? 15 Jonny

Are you using the factory recommended spark plugs/gap?

 

[F_R]

Re: Experts' what would you do next? 15 Jonny

I was going to ask that too. Have you tried NEW spark plugs? I sure would hate to know I spent $293 if it is just spark plugs.

 

[Johny25]

Re: Experts' what would you do next? 15 Jonny

I know Johnson never came out with compression specs as to how high it should be but 75 and 85 seem to low IMO. I won't bother buying a motor under 100psi in each cylinder. Maybe a decarb to loosen the rings will help? If not I say it is in need of a rebuild

How does your slow speed idle tip look? Is it worn or buggered up? And how is the packing on it? Link n sync is another I would look at as stated above.

 

[AlTn]

Re: Experts' what would you do next? 15 Jonny

is this choke only or primer system?...plugs and decarb are cheap enough...what's the spark like on the hot restart?... showing any water intrusion symptoms ? possible head gasket leak?..exhaust gasket?

 

[raczekp1]

Re: Experts' what would you do next? 15 Jonny

the problem is compresion.
put new gasket and DO THE HEAD FLATENING at auto repair shop.
wil help for sure

 

[kodibass]

Re: Experts' what would you do next? 15 Jonny

I guess a bit more history first, the first time the motor came in I did a basic tune-up new plugs (QL82c) as per evinrude.com gapped 35. I always gap 35 as some folks like 40, some like 30 (i am a simpleton by default). cleaned carb installed new carb kit, checked compression 75t 85b, checked ignition good spark both cylinders 7/16 jump on a napa spark tester. motor still hard starting after warm up. owner brought it back still hard starting after warm up. I thought it could possibly be a warped upper (plastic) carb top. But I told owner compression was at the low end and the differential range of 10 psi was considered maximum and that problems could very well be low compression problems, However the upper carb body was slightly warped. When I told the owner the cost to rebuild he said he wanted to try a new carb, his choice, I informed him it would most likely improve but may still have issues with the compression. He said to try the carb and that way if a need to rebuild it will be money well spent. His money , his rules. I just want reassurance that I'm not missing something obvious, or overlooking something not obvious. and wandering what a "real" mechanic would do

 

[jmendoza]

Re: Experts' what would you do next? 15 Jonny

Check the thermostat, it may be missing and the engine is not warming up enough to keep the plugs clean, thus they may be fouling and causing restarting problems.

 

[kodibass]

Re: Experts' what would you do next? 15 Jonny

Yep that will be done, I decided to put new rings in her, I think there were allot of little things just like that t-stat, warped carb upper, low compression, etc etc. all combined the made for an over all crappy running motor. after a rebuild, new carb, plugs ,etc. this should be a good kicker with allot of years left in it. thanks

 

[kodibass]

Re: Experts' what would you do next? 15 Jonny

so I decided to replace the rings, the cylinders look very clean/good I still see the cross hatch pattern on them. question is how should I clean them prior to ring install? I was thinking a quick 10 stroke treatment with a fine grade flex hone wipe with 1000 git w/d gas/atone air blow and call it good would this be about right or ???