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Johnson 2000 115HP Air Leak

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MikeCas

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Hi all, having performance issues, very rough running outboard, long story but I few helpful people suggested checking for air leaks in the fuel lines. Any suggestions on how to trouble shoot for that?
 
Please be more specific about your "performance issues" and "rough running outboard".

To truly get the to bottom of performance issues you should go through the full troubleshooting tree on a 2-stroke: Compression, Spark, Fuel

1) Compression - All 4 cylinders should be at or above 100PSI and no more than 10% difference

2) Spark - Use an air gap spark tester and confirm all spark plug leads will jump a 3/8" gap. Also, be certain to use ONLY Champion QL78YC spark plugs and no substitutes. These ignition systems don't do well with cross-referenced plugs

3) Fuel - You're part way there it seems.
* While squeezing the primer bulb, observe all components and fittings for leaks.
* Also, these plastic carbs were well known for the float chambers to warp and cause leaks at the mating surface with the carb body. If you find a leak at this junction your best option is to replace chamber, do not try to sand/resurface it.
* Are you seeing excessive amounts of smoke. If so, it's possible the fuel side diaphragm in your OMS pump is weak/torn and not delivering enough fuel.
* The easiest way to find an air leak is to use a can of carb cleaner with a straw and spray it on each fitting while the engine is running. Listen/watch for a change in RPM as you spray each connection. When you hear a change, then that's connection where air is getting sucked in.
 
Thank you. Here is a little explanation. (i hope)
Just got my 2000 Johnson 115 in the water. Sounded a little "off" end of last season and on the muffs this week.
New plugs, and wires, i have compression, all good with fuel, carbs cleaned with and run for about 15 minutes on OMC tune up spray. An then again the following day. After that put new Champion plugs in set to .030
Got her in the water and she shakes and just sounds awful and runs rough. Had an empty can of soda in cup holder and you could see it shake and just feel the vibration on your feet. Ran so-so wide open. RPM's around 4500 or so. Still rough and a little loud
At one point had her opened up and felt like it almost kicked in to another gear (only way i can describe it). Then about 5-10 seconds later felt like it kicked down again. It was subtle but enough were my wife even noticed and "felt" it.
Then hit a no wake zone and I was disgusted brought her in.
My skill level is beginner but I do have some mechanical skills. (I'm good at changing out parts). And I don't have any fancy diagnostic tools. I know it's vague but that's where I am.
Also not sure significance, when running on muffs I put palm of my hand over each carb one at a time and got good suction from all 3 but 4th felt much weaker than the other 3
I know it's a big ask, just hoping someone out there has an "a ha" moment. Any help or starting points? Stator? Power pack.?
 
Model # of your motor is ??----Well----" i have compression "---Means nothing.----Post the actual values that you get.-----Did you install a new water pump impeller when you got the boat , yes or no?-----Drain gear oil and see if there are any metal bits on the drain plug magnet.-----Running with a tested VRO pump or mixing at 50:1 in your tank ?
 
racerone said:
Model # of your motor is ??----Well----" i have compression "---Means nothing.----Post the actual values that you get.-----Did you install a new water pump impeller when you got the boat , yes or no?-----Drain gear oil and see if there are any metal bits on the drain plug magnet.-----Running with a tested VRO pump or mixing at 50:1 in your tank ?
Click to expand...

Johnson J115VLSSS​

i'll get the compression readings later in the week and report back. re: Other questions...Did not install new impeller on water pump. did not see any metal bits on magnet plug, running with working VRO pump.
 
MikeCas said:
New plugs, and wires, i have compression, all good with fuel, carbs cleaned with and run for about 15 minutes on OMC tune up spray. An then again the following day. After that put new Champion plugs in set to .030
Got her in the water and she shakes and just sounds awful and runs rough........ opened up and felt like it almost kicked in to another gear (only way i can describe it). Then about 5-10 seconds later felt like it kicked down again.
And I don't have any fancy diagnostic tools. I know it's vague but that's where I am.
I put palm of my hand over each carb one at a time and got good suction from all 3 but 4th felt much weaker than the other 3
Click to expand...
No fancy tools really needed. A spark gap tester (less than $10 at O'reilly's), a Multi-meter (Less than $25 almost anywhere) and a free compression gauge (on loan from O'rielly's) will help you diagnose this engine.

As Racer said "I have compression" isn't enough. You need the gauge and exact numbers. Also, giving the full beans to a poor running engine almost never solves anything and likely will cause more damage if there is a big problem.

I would be concerned with that 4th carb that had almost no suction. When placing your hand over a carb throat you should hear and see a noticeable change in running attitude of the engine. If that 4th carb had significantly lower suction and didn't make any change to the way it runs you might have low compression on that cylinder.

Finally, installing new plugs is a perfectly good maintenance practice. However, replacing spark plug wires usually isn't needed unless there is a diagnosed problem. Using the air gap spark tester will tell you if you have a problem with ignition on each cylinder.
 
kevinj said:
No fancy tools really needed. A spark gap tester (less than $10 at O'reilly's), a Multi-meter (Less than $25 almost anywhere) and a free compression gauge (on loan from O'rielly's) will help you diagnose this engine.

As Racer said "I have compression" isn't enough. You need the gauge and exact numbers. Also, giving the full beans to a poor running engine almost never solves anything and likely will cause more damage if there is a big problem.

I would be concerned with that 4th carb that had almost no suction. When placing your hand over a carb throat you should hear and see a noticeable change in running attitude of the engine. If that 4th carb had significantly lower suction and didn't make any change to the way it runs you might have low compression on that cylinder.

Finally, installing new plugs is a perfectly good maintenance practice. However, replacing spark plug wires usually isn't needed unless there is a diagnosed problem. Using the air gap spark tester will tell you if you have a problem with ignition on each cylinder.
Click to expand...
Thanks Kevin, appreciate the feedback. Autozone does have the gauge availble so this weekend I'll get on that and other suggestions. I kept the wires I removed so maybe since it's an easy enough job I'll put those back on just for the heck of it...Will report findings next week..thanks again
 
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