should i be worried about this on my comp on motor

[tlyonshunter]

2004 johnson 150 just had rebuilt maybe 50 hrs ago?

Well had a chance to check your motor. You have low comp. on #6 cyl. It's still 100 lbs but compared to the others it's low. That will cause what you said your boat is doing. Link and sink is ok. The plugs look great all 6 a nice dark brown. I think the motor will be fine but it won't run quit as good as it did. The only option is a new power head and your talking $3000 to $4000 or more I haven't priced one in a while. I would just run it like it is. I'm going to run it on the Dyno tomorrow make sure everything else is ok.
#1 120
#2 110
#3 120
#4 110
#5 110
#6 100

[Buccaneer]

Huh? 2004 150 Johnson Carb? They don't have computers, or at least that is what I have been told? If so I am going back to my dealer and kicking some A$$. I thought only Evinrudes from that model year had diagnostic capability.

[Buccaneer]

Ooops sorry Todd, saw "comp" and went brain fart nutty. I would not think 100 lbs comp in any cylinder is "low" but isn't there a % range between all cylinders that you need to be within? What about a dose of Seafoam in a tank and see what happens?

[tlyonshunter]

Yes i meant compression no computer on johnson i have been told 10% variance (spell) is ok

[Danrude]

I would do a good de-carb on the motor and see if that #6 cylinder would come up. Use BRP engine tune and follow the directions on the can. Do not perform on muffs while parked on driveway.

[fast fred]

You can do it with muff just not in the driveway. The mixture of the tuner and the carbon coming out of the motor will stain concrete and will make your wife very mad. And according to your numbers if I'm reading them correctly:
Port side: Starboard side

2=110 1=120
4=110 3=120
6=100 5=110

It is normal for the two lowest cylinders to be slightly lower. Those are the very bottom two and all the exhaust goes past them.

As Danrude said a good decarb with BRP engine tuner should fix you right up.

[tlyonshunter]

Motor has less than 30hrs on rebuild do you think i need to still decarb ? Motor has not run the same since rebuild .

[Danrude]

Yes! You have been running double oil for breakin.

[tlyonshunter]

thank i will try it this weekend