Johnson 150 Rebuild/Remanufacture Guidance

[Terrapin]

I plan on mounting my powerhead this weekend and am very close to initial startup. Please review my start up plan below and provide guidance. I realize, it is what I don’t know that will kill me! So what am I missing?

Check spark on all cylinders using a 3/8” gap (in driveway).

Check linkage on carb for throttle plate sync and proper roller cam follower pickup position.

Use piston stop to set top dead center timing indicator on #1 cylinder

Use the Joe Reeves timing procedure (in driveway) to determine whether WOT is set properly. My OEM Service manual specifies 32 degrees BTDC. I want to retard the timing (during engine break in) 2 to 4 degrees per what I have read. Per Joe Reeves, shoot for 4 degrees less than desired WOT set point given CDI electronics particulars. Therefore, I am looking for 24 to 26 degrees using the Joe Reeves method in the driveway. The engine ran fine before this so I’m thinking it should be fairly close to this now.

I am not close to any big water I can run on close to me, but will use a boat ramp at a local and shallow river.

The following is gleaned from the Master Tec site:

Try to start up in a manner that does not cause high engine RPMs. This may be a challenge given prior to the rebuild I would have to open up the throttle a bit to start.

Start up, (on trailer in water at ramp) check for leaks and ensure water circulation. Use thermal gun to monitor head temps. I have a pressure gauge to check/confirm water pressures.

Check the pick up timing with the throttle advanced to the first mark (past cam follower pick up position) on the cam. Adjust to 7 degrees BTDC.

First 20 minutes (on trailer in water at ramp): Run at high idle (750 to 850 RPM) out of gear. After this, the Master Tec sight says “check the plugs”. What does that mean?

20 minutes to 2 hours (on trailer in water at ramp): Run up to 1500 RPM loaded in gear and vary the speed from idle.

2 hours to 8 hours: Set idle on water with boat in gear and free to move at 650 RPM. Run the boat in water and cruise at 3000 to 3500 RPM (when doing so, don’t lug the engine, get the boat up on plane and then throttle back the RPM). Periodically, give it short runs up to full throttle (5000 to 5500 RPM).

Re-torque cylinder heads after 10 hours of run time and engine cool down.

After break-in period set WOT two degrees retarded at 30 degrees.

 

[racerone]

Running on the trailer at the ramp for 2 hours ???------What if you are running mud / sand through the water pump for 2 hours.

 

[Faztbullet]

You can do a OMC/BRP factory break-in in a 1-1/2 hours. I break in all my customers this way. Need test prop and some big water

 

[Terrapin]

I will make a test prop by removing an inch from the end of an old 14 1/2 x 19 aluminum prop.
My Service Manual states the following for Break-In Procedure:

• First 5 - 10 minute, operate engine at a fast idle.
• Remainder of First Hour: Engine should be operated at boat planing speed, but not over 3000 RPM. Get boat on plane and then back off throttle to avoid lugging engine.
• Second Hour: Bring boat up on plane and reduce power to 4000 RPM. At intervals during the second hour apply full power for periods of one or two minutes, returning to 4000 RPM.
• Next 8 Hours: Avoid continuous full throttle operation for extended periods.

Faztbullet, please provide me details on your suggested break-in procedure, and when I use the test wheel.
Also, is my above plan for setting up the timing ok, or am I missing something? Thanks!

 

[Terrapin]

You can do a OMC/BRP factory break-in in a 1-1/2 hours. I break in all my customers this way. Need test prop and some big water

Alan, I already set the timing using the Joe Reeves method in the driveway. Actually, I didn't have to move the current setting as I confirmed I am 2 to 2 1/2 degrees retarded.

Using the test prop, at what point in the break in period do I run it up to 5500 RPM and set the WOT timing retarded 2 degrees at 30 degrees?

 

[Faztbullet]

Check your pm

 

[Terrapin]

Backed the boat down the ramp with my home made test prop, hit the primer five times, turned the key and it fired right up! While this was what I hoped for, I was amazed it did not take a bit of coaxing to get her running. When the initial puff of smoke cleared, the tell tail was streaming nicely and my pressure gauge was showing nice pressure. What an awesome feeling!

I monitored the water pressure with a quality WIKA water pressure gauge for more detail, instead of my console’s water pressure gauge. In addition, I monitored the engine temp with an infrared gun. All were looking good and no water leaks were visible.

I performed the suggested OMC/BRP factory break in and set the WOT timing 2 degrees retarded at approximately 5200 RPM.

A few days later I was off on a family vacation and put an additional 35 to 40 hours on the engine. It seems to be running better than ever and trolls very nicely. The rebuilt reed cages with the Chris Carson sport reeds may be contributing to the nice idle and smooth trolling speeds. It now takes a little priming action on start up to get her warmed up. I may have to try (as suggested by Faztbullet) idle air jets that are .001” smaller to richen up the fuel at idle.

Although I’m mechanical, I’ve never rebuilt an engine before. I can’t thank the forum members which contributed enough for the help, with what was a long drawn out rebuild. Special thanks to Faztbullet for the many tips including using Jay’s Block Shop (highly recommended) for the bore and hone work. Plus, reaching out to me to provide detailed break in guidance and support. Racerone, thanks so much for your support also!

I’m hoping I get many more years out of this engine. Thanks again!

 

[ct1762@gmail.com]

the smooth idle mostly has to do with Jay's awesome work. I only use him now. Never going back to anyone else unless i have to!

 

[Faztbullet]

I will tell Jason of the accolades posted about his service. Jason and I have long history together.

 

[Terrapin]

Yes, Jason at Jay's Block Shop was great to work with, his service was quick and he did a very nice job on my block. I was impressed he was able to clean up my cylinder scoring by only going .020" oversize.