Johnson Oceanrunner 150 " Just Quit"

Hi Guys I'm new to this forum and in need to some serious answers!. I have a 1994 ocean runner V6 150. I have had this boat/motor for less then 6 months. I had it checked out by our local boat shop and they adjusted my controls and gave it a clean bill of health. I was on the water this weekend and had been towing my grand kids around when all of a sudden the engine slowed down and just quit. I checked the fuel bulb and it was tight. I checked the VRO oil reservoir and it was still full. the alarm on my controls didn't go off for the VRO. I never changed the impeller when I first got the boat, and when I had the shop check it they said it was fine. Does this engine have a thermostat?. Could it have overheated?. When I got back home I took a compression check on all 6 cylinders and found the starboard side lower piston had only 55 PSI. All of the other ones had 120 PSI. looks like I'll be rebuilding a power head!!. Can the power head be rebuilt with the block still attached to the lower unit?, or does the whole thing have to come out and be separated?. Any suggestions on a place to pick up parts where you won't get raped?. I have pretty much a complete machine shop here in my house so the machining process will be done right here!!. any and all replies are much appreciated in advance. Thanks Allan

Re: Johnson Oceanrunner 150 " Just Quit"

Heres some rebuild kits that I've seen posted here.
http://www.powerheadkit.com/johnson.htm

I don't take anyones word any longer on my outboard, new to me with unknown service history would automatically mean rebuild carbs, water pump, gear oil , replumb hoses etc etc.

Seems futile but you might want to try a seafoam soak on that low cyl in case it has stuck ring. As if we have such luck.

Re: Johnson Oceanrunner 150 " Just Quit"

You'll need the service manual
www.outboardbooks.com

and an engine hoist, powerhead has to come off.

Rebuild that carb and expect to find something clogging the fuel flow.

Re: Johnson Oceanrunner 150 " Just Quit"

Do you think it a result from fuel flow?. If so why were the other pistons not affected or where they?.

Re: Johnson Oceanrunner 150 " Just Quit"

Can I pull the powerhead with the lower unit still attached to the boat?

Re: Johnson Oceanrunner 150 " Just Quit"

flyboyziel56 said:

Do you think it a result from fuel flow?. If so why were the other pistons not affected or where they?.

Click to expand...

Yeh thats why I wrote "rebuild THAT carb"

No fuel is no lube and a clogged carb runs that cylinder dry, each cyl has its own carb.

Re: Johnson Oceanrunner 150 " Just Quit"

flyboyziel56 said:

Can I pull the powerhead with the lower unit still attached to the boat?

Click to expand...

I believe so,
disconnect tilt elec wiring plugs, fuel and oil bracket from lower cover, remove lower covers , disconnect shift linkage.
remove screws connecting head to exh housing and steering arm bracket, attach hoist and pry loose.

Re: Johnson Oceanrunner 150 " Just Quit"

OK!, just a stupid question!, If the Single Carb is the reason I lost compression on the lower piston, then depending on the damage ie, scored wall burnt piston, then the overhaul on the rest of the powerhead could be limited to a ring job with gaskets right?. If I replace the 1 piston and rering the rest i should be in good shape?.

Re: Johnson Oceanrunner 150 " Just Quit"

Excellent possibility! Especially if it didn't overheat. Id be cautious using your in house machine shop. I understand that outboard have some unique machining requirements.

PS - I would rebuild ALL the carbs.

Re: Johnson Oceanrunner 150 " Just Quit"

Well I did manage to hobble it back to the dock where my trailer was. That was about 2 miles out, so under an idle it never quit once it was restarted back up. During the compression check it really never got hot not even the bad cylinder. The only thing I hope could be bad is the rings are collapsed. Maybe the cylinder is scored so the machining would be limited to honing out the cylinder!!

Re: Johnson Oceanrunner 150 " Just Quit"

Pop the head off and inspect the cyl wall.
Intake and exh ports should be ported or relieved so they don't snag the rings.
You might get by with just one cyl clean up and ring job.
Take a look and call the parts guys, they'll tell you which gasket set and parts to order.

If you do a good job , we'll send you our engines.