Johnson 150 Ocean Pro Carburaters

[AndyD]

I have 1999 Johnson Ocean Pro 150 carburated model. I have had this about 6 months. The boat and motor had very low hours on it when I bought it (about 30-40 hrs). The rig was purchased new in 2001 so over the course of 8-9 years it was used very little by the original owner and I'm sure that it sat unused for extended periods of time.

When I purchased the boat it had a nearly empty fuel tank. I immediately treated the fuel with stabil, filled the tank with new fuel (50 Gals. on a 65 Gallon tank - yes, I know I should have siphoned it all out), drained the carburetor bowls, Cleaned the fuel screen and installed a water separating filter. I've also treated the fuel with Bombardier fuel injector cleaner.

My engine usually starts OK and runs a little rough until warm. extended idling will cause it to idle rough, cough sputter and stall. If I can get it up on a plane for a few minutes it will idle quite nicely for a while but this gradually deteriorates, and at any speed other than idle it runs like a champ. Now If even if the motor has been idling good and I turn it off and let it sit for a while I'm back once again to the rough Idle, hard starts and stalling. I'm pretty well convinced that carburetors are what's ailing my motor as I know the previous owner did nothing to the boat or motor. The hours however were so low and the price so good that this was hard to pass up so I can afford to work out some bugs.

I suspect that I will need to remove and clean the carbs. I think I've done about everything I can do short of that to correct any fuel problems. This looks like something I can tackle myself. I used to do this often on my old crossflow V-4 years ago. From looking at the manual and inspecting the setup on the engine this looks like a relatively straightforward affair especially since the fuel metering bodies are separate from the throttle bodies and linkage assemblies. This looks to be an advantage since unless I touch something I'm not supposed to I should not disturb the engine synchronization. My manual (Seloc) states that I should do a Link & Sync after cleaning carbs. My question for the experts out there is whether this is really necessary as I'm don't plan on disturbing anything, and will be replacing and tightening bolts on the TB as I remove each carb. Finally, are there any tips, tricks or anything I should be aware of that is not explicitly mentioned in the manual. I've been bitten in the past when something was omitted from a manual.

 

[Chris1956]

Re: Johnson 150 Ocean Pro Carburaters

I have a '98 Johnny 150HP V6, which is pretty similar to yours. Each of it's six carbs has an idle mixture adjustment. It is likely that due to some dirt in the carb idle passages or even someone messing with the adjusters, the mixture is a bit off. I had a problem very similar to yours. When I bought the boat, it would idle all day perfectly, however, three years later, it will almost stall after extended idleing.

I removed, cleaned and rebuilt the carbs w/o disturbing the idle mixture setting. There was no signb of dirt, BTW. The motor idles better, but not as good as originally. One of the other ideas I have is that the fuel recirculation system is dirty. You might check that as well.

Let me know how it goes.

 

[AndyD]

Re: Johnson 150 Ocean Pro Carburaters

Thanks for the reply.

From searching the threads here this seems to be a very common problem. I'm keeping my finger crossed a good carb cleaning is the solution.

I'll be getting some kits soon and performing the cleaning. I'll post back after I've had the chance to do it.

 

[jonesg]

Re: Johnson 150 Ocean Pro Carburaters

"My question for the experts out there is whether this is really necessary as I'm don't plan on disturbing anything, and will be replacing and tightening bolts on the TB as I remove each carb. Finally, are there any tips, tricks or anything I should be aware of that is not explicitly mentioned in the manual. I've been bitten in the past when something was omitted from a manual. ""

If you have the plastic carb bowls then you only need to remove that part of the carb, the throttle body with the butterfly valves is not disturbed.

But its a lot easier to check all the butterfly's are aligned when the carbies are out of the way.

 

[AndyD]

Re: Johnson 150 Ocean Pro Carburaters

Update;

Well, I went out to the local dealer and purchased the needed kits and rebuilt all 6 carbs today. Everything seemed to go well. The passages I looked at did not really looked gunked up to me, although there was some nasty black crud on the exposed areas of the brass parts. It took me about 6 hours mostly because I was taking my time and being meticulous.

I left the TB's on the motor. I was able to remove the idle port covers on the stbd side, but on the port side I just flushed with engine tuner and blew out with compressed air. One note though The kit came with a nylon seal for the float needle seat. The carbs didn't come with one originally and installing it prevented a proper adjustment of the float height, so I left it out.

Long story short... I completed the job and fired her up on the muffs. To my complete satisfaction the motor fired up on the first turn of the key, without using the primer, did not stall, or require and additional throttle to keep it going until warmed up (never did that before). Formerly I was running about 1100 RPM on the muffs, now it runs about 850 RPM on the muffs. We'll have to see what it runs at in the water. I'm hoping to get out and test it tomorrow. My guess is that the higher RPMS were must have been due to a lean idle condition. I think that is a symptom.

 

[Chris1956]

Re: Johnson 150 Ocean Pro Carburaters

Andy, I too needed to leave out the nylon washer. It is good to have some validation that it was the correct move.

Let me know how the water test goes.

 

[jonesg]

Re: Johnson 150 Ocean Pro Carburaters

Update;

Well, I went out to the local dealer and purchased the needed kits and rebuilt all 6 carbs today. Everything seemed to go well. The passages I looked at did not really looked gunked up to me, although there was some nasty black crud on the exposed areas of the brass parts. It took me about 6 hours mostly because I was taking my time and being meticulous.

I left the TB's on the motor. I was able to remove the idle port covers on the stbd side, but on the port side I just flushed with engine tuner and blew out with compressed air. One note though The kit came with a nylon seal for the float needle seat. The carbs didn't come with one originally and installing it prevented a proper adjustment of the float height, so I left it out.

Long story short... I completed the job and fired her up on the muffs. To my complete satisfaction the motor fired up on the first turn of the key, without using the primer, did not stall, or require and additional throttle to keep it going until warmed up (never did that before). Formerly I was running about 1100 RPM on the muffs, now it runs about 850 RPM on the muffs. We'll have to see what it runs at in the water. I'm hoping to get out and test it tomorrow. My guess is that the higher RPMS were must have been due to a lean idle condition. I think that is a symptom.

1000 rpm on the muffs is ok, 850 might be a bit too slow.
But you don't know until its in the water, then you'll find out.
Mine runs like crap on the hose but perfect in the water.

In the water , in gear , at idle the rpm should be around 750 or 700.
If it quits when put into gear the idle is probably too low.
Or if it stalls when placed in reverse the idle is set too low.
They typically idle rough until warmed up, its normal to keep bumping the choke when its cold to keep the rpm up and advance the throttle slightly, take it out of gear to do this. I find mine warms up in less than a minute.

Check this on your engine.
http://bbcboards.zeroforum.com/zerothread/357667-throttle-roller-timing-arm-adjustment-60-motors

 

[AndyD]

Re: Johnson 150 Ocean Pro Carburaters

Sea Trial,

Had her out on the water today. The motor was idling too low and stalling when put into gear. I went fishing close to the boat ramp as I didn't wasn't to go too far till I worked out all the bugs. Noticed when pulling boat out of the water some fuel dripping when I tilted the motor up. When I got home I pulled the cover while flushing and noted fuel coming out the discharge tube on the bottom stbd carb. I figured it must have been a float problem. I pulled the carb, swapped the float with an old spare and checked height & drop, reassembled, and installed. On firing up the leak was fixed, and idle is now 1050 RPM on the muffs. Not sure but figure I must have messed something up when adjusting the float. Bending a thin little piece of skeet metal with a pair of needle nose does not always make for high precision calibration. I know what to watch out for in the future.

On a side note I've got to say that these carbs are actually a pleasure to work on compared to my old crossflow V-4. My last was a 1.4 ltr Sea Drive. Unlike the old cardboard gaskets should you need to take apart something you just assembled you don't necessarily have to have a new gasket. Cardboard was pretty much toast. But then the cardboard gaskets were cheap too. They are real proud of these new ones ($$).

 

[jonesg]

Re: Johnson 150 Ocean Pro Carburaters

Thats the ticket, 1050 on the hose is good,
in the water your idle will be spot on and it will not quit when shifted into gear. You just saved $600, spend it wisely...on fuel.

 

[AndyD]

Re: Johnson 150 Ocean Pro Carburaters

Almost got it nailed.

Took it out on the water today for a quick sea trial however I am still getting some lean sneezing and stalls. Got her back to the house today, put it back on the muffs and figured I'd do some live troubleshooting. Started out at 950 RPM I got out my allen wrench and went through each carb turning out the idle screw one at a time. At 5-1/2 turns on the port bottom carb the idle smoothed out and RPMs back up to 1100. So I think I've isolated the area of the problem. Now what to do to correct it. Any suggestions?

I'm heading back out to the driveway right now to pull the suspect carb AGAIN, and recheck the float level, and while I'm at it it I will blast the idle port with engine tuner and compressed air. This is about all I can think of. I did note that the holes for idle fuel on the side of the TB are VERY VERY small so it wouldn't take much more literally than a speck of dust to plug them.

By the time I'm done I'll be a carburetor expert.

 

[AndyD]

Re: Johnson 150 Ocean Pro Carburaters

Update again,

Found a cut spaghetti seal on this carb. Understandable since this was the most difficult carb to get on and off with all of the wires and hoses in the way. replaced with UBG, blasted Idle port. I set all idle screws at 4-1/2 turns which smoothed out idle and turning Port bottom to 5 turns eliminated the last bit of stutter. RPM's now at 1200 on the muffs but no more sneeze and stutter.
Is it OK to run the idle screws out a bit? The book calls for 4 turns.

Will Ssea trial again tomorrow.

 

[Chris1956]

Re: Johnson 150 Ocean Pro Carburaters

The service manual gives initial idle mixture settings. Normally they need to be adjusted on the water under load at idle. Try to leave the idle mixture a bit richer, as it will help with acceleration.

 

[jonesg]

Re: Johnson 150 Ocean Pro Carburaters

Update again,

Found a cut spaghetti seal on this carb. Understandable since this was the most difficult carb to get on and off with all of the wires and hoses in the way. replaced with UBG, blasted Idle port. I set all idle screws at 4-1/2 turns which smoothed out idle and turning Port bottom to 5 turns eliminated the last bit of stutter. RPM's now at 1200 on the muffs but no more sneeze and stutter.
Is it OK to run the idle screws out a bit? The book calls for 4 turns.

Will Ssea trial again tomorrow.

Those seals are fragile, hold them in place with a smear of grease.

 

[AndyD]

Re: Johnson 150 Ocean Pro Carburaters

Last Update;

Took her out on the water today. Tied the boat to the dock and adjusted idle till it ran nice and smooth. I'm at around 5 - 5-1/4 tuns on all carbs which is 25% higher than the book values but the motor idles smoothly at about 850 RPM in gear with no sneezes, or stutters starts on first crank, and shifts nicely with no hesitation or stalling. The only thing I've got which I had before is a slight shake or vibration between 1000-1200 RPM only in gear. This must be a harmonics thing since the engine appears to, and sounds like it runs smooth while it's doing this with no misfires or anything. I might be the only one who notice it since I asked my wife and she didn't notice anything wrong. Hopefully this will help someone else in the future. Thanks Jones & Chris for your input.