Johnson 1968 33hp

[boatbeginner1]

Re: Johnson 1968 33hp

Good!

What is the vacuum cutout? When I looked at it, It looked like the PO had messed with wiring. There were wires that were too short so he connected them and he/she mixed colors of wires etc.

How do I fix/replace these? Do I need to? I plan on starting the engine, or attempting to, in the next couple days.

 

[kfa4303]

Re: Johnson 1968 33hp

Hello again. I would not try to start the motor until you have the wring straightened out. This link may be helpful.

http://forums.iboats.com/showthread.php?t=106960

 

[boatbeginner1]

Re: Johnson 1968 33hp

Alright! Thanks for the advice! That is very hard to read though... Is there a clearer one?

 

[boatbeginner1]

Re: Johnson 1968 33hp

Yup, I do think its mostly original. The starter and starter bracket likely came off of another engine, but they are the same as what your motor would have had.

One thing that does bother me about your motor, however, is the red wiring going to the vacuum cutout. The circuit involved is a ground, not a "hot" circuit, so the wires should be black. If the unit is actually wired as a ground, you're OK, but you should double check. The purpose of the cutout switch is to "kill" one of the coils in the event of an rpm runaway, which can sometime happen if you pull power off too quickly.

What is the vacuum cutout? Do you need more pictures of the engine?

 

[kfa4303]

Re: Johnson 1968 33hp

Hi beginner. Here's a labeled pic of the cut-out switch.

 

[lindy46]

Re: Johnson 1968 33hp

Sure looks like an extra wire going to that cut-out switch - to the 12 volt terminal of the starter. That IS NOT correct. There should be no 12 volt hook-up to that switch. Maybe that wire is passing behind the starter terminal? It's hard to tell from the picture.

 

[kfa4303]

Re: Johnson 1968 33hp

Yeah, the pic of the wiring in the front in a bit of a rat's nest too. Might be best to just rip it all out and start from scratch :/

 

[boatbeginner1]

Re: Johnson 1968 33hp

How much extra wire/time wi this take. I know little about outboards...

 

[kfa4303]

Re: Johnson 1968 33hp

Once you got the tools and materials, it would only take one afternoon to do. All of the wires are readily available sizes and use standard connections. The trick is to be very methodical and systematic when doing electrical work. I would start by getting the wires on the motor itself are in order, making sure that it starts and runs by using simple manual start. Once you've confirmed that the motor runs well, you can then move on to the accessories such as the electric starter, choke and controls. However, before you do any of that make sure the motor has good compression (over 90 psi in each cylinder), or all the electrical work in the world won't do you any good.

 

[boatbeginner1]

Re: Johnson 1968 33hp

Alright. What tools and materials will i need? Im going to try to borrow a compressions tester from my neighbor but I might need to go and buy one.

How do I start the boat with manual start?

 

[kfa4303]

Re: Johnson 1968 33hp

Hello again. No special tools needed, just a regular automotive-style compression tester which you should be able to rent/borrow from the store. You start by removing the spark plugs and disconnecting them from the s'plug wires. You then thread the tester into one of the cylinders where the s'plugs were and pull start the motor 4-5 times. Make note of the figure on the tester and repeat the procedure on the second cylinder. With any luck the figures will be over 90 psi and within 10% of each other. If you have a large disparity between the two cylinders you may have bigger problems. You can also spray a bit of Deep Creep/WD-40 into each cylinder prior to testing to help loosen things up a bit, which may improve the compression stats. Here's a vid of a guy doing a comp test.

Compression Test on 1962-3hp Johnson Outboard Part 1/2 - YouTube

 

[boatbeginner1]

Re: Johnson 1968 33hp

Ok!compression testing seems easy. Concerned about wiring. How do I manual start, no electric?

 

[jay_merrill]

Re: Johnson 1968 33hp

What is the vacuum cutout? Do you need more pictures of the engine?

Sorry to be so long in answering. I actually posted a response a day or so ago, but it seems to have gotten lost in the depths of computer hell!

Anyway, first thing is that there should not be any wires from the "hot" side (12vdc) attached to the cutout switch. Its purpose is to act as a ground for one of the ignition coils. That being the case, you want black wires, properly circuited to the ground side of the electrical system.

Your motor, along with a number of other OMC models, has a tendency to overspeed, if the throttle is retarded too quickly. This problem is related to high vacuum created by the motor under this condition. The vacuum cutout switch senses the high vacuum and closes a ground circuit to one of the ignition coils. With one cylinder then inoperative, the motor won't overspeed and cause damage to itself.

In everyday use, this condition isn't very likely to occur, but it can and it is important to make sure that the switch both works and is wired correctly. I am generally not a fan of Clymer and Chiltons outboard manuals, but they do have pretty good wiring diagrams for the OMC brand motors. I recommend that you get you hands on a diagram for your motor and run through the entire electrical system, to make sure everything is as it should be.

 

[boatbeginner1]

Re: Johnson 1968 33hp

I have no experience with outboards so I'm getting confused about the parts. Could you use te picture and draw a line fr me? I know what the vacuum cutout does now but what's the 12vc?

 

[lindy46]

Re: Johnson 1968 33hp

The cut-out switch should have (and does in your pic) 4 wires going to it. The white wire from the side terminal going up to the safety switch under the flywheel is correct. The other wire on the same side terminal should go to one of the small terminals on the starter solenoid. Your pic is unclear on that one. The two wires from the center terminal: one should go up into the underside of the armature plate and attach to one set of points. The other wire should go out to the wiring harness and on to the "M" terminal on your ignition switch. Any other connections/splices to that switch should be eliminated.

 

[jay_merrill]

Re: Johnson 1968 33hp

I have no experience with outboards so I'm getting confused about the parts. Could you use te picture and draw a line fr me? I know what the vacuum cutout does now but what's the 12vc?

"12vdc" stands for 12 volts, direct current. Automotive and small boat electrical systems generally use this system, while your home generally uses 120 volts, alternating current for small appliances. lights, etc. and 240vac for your dryer, water heater, stove, etc.

 

[boatbeginner1]

Re: Johnson 1968 33hp

Alright. Il look at it Sunday when I get home. Does it look correct from the pictures? Te front of the engine has a bunch of wires that look like they were to short so te PO just added a small piece of wire and it does not look neat. Do I need to replace that or can I put a wire coupler at the two ends?

Last thing, is the only way to start my engine using the electric ignition or can I manually start it?

 

[boatbeginner1]

Re: Johnson 1968 33hp

I got a compression Tester. I hope to test today or tomorrow. As far as the vacuum cutout switch goes, do you guys need more pictures of the engine head? I can post those.

 

[boatbeginner1]

Re: Johnson 1968 33hp

So went to compression test...got the spark plug out put tester in. So far so good. Then relized could not start engine so I went to put the plug back in than "Houston we have a problem." The bottom spark plug will not screw in. I keep screwing and screwing and screwing, it wont get tight... Anybody, please, HELP!!!!

 

[jasper60103]

Re: Johnson 1968 33hp

So went to compression test...got the spark plug out put tester in. So far so good. Then relized could not start engine so I went to put the plug back in than "Houston we have a problem." The bottom spark plug will not screw in. I keep screwing and screwing and screwing, it wont get tight... Anybody, please, HELP!!!!

The compression tester adapter is probably the cause of stripping the spark plug hole.
It can be repaired, but I'm not sure the best course of action for an old engine and likely rusted bolts.

Hopefully others will chime in with some helpful advise.

edit: Regarding the compression tester. The end that you screw in the spark plug hole should have an o-ring (like in pic below). You shouldn't need to use an adapter. Good luck.