1972 johnson 65 hp ob 50th edition

Hey guys newbie here and need some advice i was just recently given a boat and was told that when it was last used probably about 15 years ago that it was in mint condition motor and boat when it was parked and never been in the water since guess my ? is how do i go about seeing if this boat/motor will start or run i don't have the funds right now to take it to a shop or have no idea what they might charge me to look at it can ya'll tell me a ballpark figure or what steps i should take to see if motor runs it looks like it's in mint condition when you pull the cover off everything looks greased up on it just needing a little guidance on how to proceed with this i really like to restore this boat any advice anyone!

Re: 1972 johnson 65 hp ob 50th edition

Hello agian just ckecking to see if anyone has replied back since i'm also new to this site i don't know if i'm looking in the right place for replies pls help and thanks again.

Re: 1972 johnson 65 hp ob 50th edition

My advice at the very least is to replace the rubber impeller in the water pump with a new impeller. They are cheap to replace, designed to be replaceable, and serious problems will result if it fails due to lack of replacement. Do I sound a bit biased? I would hate to see your old classic wrecked due to the broken rubber impeller vanes clogging the water passages and ruining an otherwise good motor. Look into it for sure!

If you motor had any residual fuel in it all those years ago when it was decommissioned, well there is also a good chance that there is some gummy junk in the carburetors. Not doing anything, then running your motor with a clogged carb or two can lead to disaster. If a passage in a single carb is blocked, not only is the cylinder that relies on it starved for fuel, it is also starved for lubricating oil. Carb synchronization with proper tool (after they are completely cleaned) will go a long way toward economy, emissions, power and longevity. All cylinders will be working equally. What?s the old expression? ?You can pay me now, or you can pay me later...? (with interest!)

Change the lower unit gear lube, remembering that you have the last of the hydro-electric drives and need to use the thinner, more appropriate lube.

If it all sounds like preventative maintenance, it really is. Preventative maintenance will go a long way with that motor, so my advice is to do it for sure.

Re: 1972 johnson 65 hp ob 50th edition

Very first thing I would do is take out the spark plugs and try to turn the engine over by turning the flywheel. If it turns, it is not siezed and is probably worth investing a few dollars. Don't let the oily motor scare you. It was probably oiled to protect it from corrosion. Now buy a service manual specific to that motor. You will have to dismantle the carbs and scupulously clean every orfice. Install new sparkplugs. Get a good marine battery for it. Obtain an outboard (muffs)flush device so you can run it on the garden hose. DO NOT under any circumstance try to start it without running water through it. Fuel must be mixed with two-stroke outboard oil at a 50:1 ratio.

Good luck and have fun!

Re: 1972 johnson 65 hp ob 50th edition

The 1972 Johnson 65p motors can be great motors or money pits, depending on condition when you acquire them. I have one that I bought over three years ago and have been very happy with it.

Do not try to service this engine without a factory manual. Forget the aftermarket manuals and all of the bogus CD/DVD manuals that "everybody and his brother" is trying to sell on the internet. You need the real deal.

The first thing that you need to do, is to assess the mechanical condition of the motor and the condition of the hydroelectric shift system. Problems in either area can make refurbishment "iffy" in terms of simple economics. Do a compression test first thing. I would be looking for 120psi or better, with no more than 10% differential between cylinders. Then test the shift system. You will need the manual for instructions on how to do this.

If you decide to rebuild the water pump, be very careful when you lower the gearcase from the midsection. [b}Do not[/b] let it fall from the midsection as you remove the last bolt. There is a wiring harness inside that is an NLA item - if you break the wires, you are pretty much SOL!.

A typical refurbishment punch list for this motor would be:

Compression test.

Check shift switch (control box) and shift solenoids for proper operation.

Rebuild carbs, link & sync.

Set timing.

Rebuild fuel pump or replace.

Rebuild water pump.

New gear oil - use BRP "Premium Blend" (Type C equivalent).

Check/replace thermostat.

Check condition of pressure release poppet valves in cooling system.

Check Hot Horn operation.

Check for compliance with OMC Service Bulletin 1335, Warm Up Choke.

Spark check - use gap tool.

Stator - ohms test.

Timer base - ohms test.

Charge system output check - replace rectifier if needed.

Spark plugs - use Champion "j plugs" only. Do not use other brands, especially NGK. I use L77JC4 in mine, with good result. Some people recommend QL77JC4, but this engine does not have optical sensors, etc., that benefit from the QL plugs.



???

Re: 1972 johnson 65 hp ob 50th edition

hi guys this motor is just turning over but won't start how would i check for spark to the plugs i can smell gas getting to it and it also seems to be leaking gas out from somewhere in the motor any ideas

Re: 1972 johnson 65 hp ob 50th edition

Run a search o spark check, I beleave it will show you how to make a spark checker, or they are available at most auto parts stores. You need to make sure you have a fully charged battery. Is the gas fresh and has the proper amount of oil mixed in it? It is not uncommon to smell a little gas when trying to start an engine that has been sitting for awhile.

Do you have the choke set in the proper place, Auto or manually on, could cause excessive gas out of carbs.

Re: 1972 johnson 65 hp ob 50th edition

Read this thread.

http://forums.iboats.com/showthread.php?t=158086

Re: 1972 johnson 65 hp ob 50th edition

Tacklewasher said:

Read this thread.

http://forums.iboats.com/showthread.php?t=158086

Click to expand...

Thanks a bunch that is a great start since i'm very new at this and will probably need lots more help to tackle this on my own since my funds can't afford a real mechanic. I also inherited the factory manual with the boat and motor. any more help is always appreciated you guys are great!!