Hard To Start : 1966, 6HP Johnson Engine.

[Jack Letby]

Ref. : 1966, 6HP Johnson Model "CD23E" Sea - Horse Motor.

Dear Forum.
My 1966 Johnson 6hp motor is hard to start, spent its life as an auxillary, not a lot of running time and no rust. The carburetor has been fully serviced, and it has a good spark. A compression test over about four pulls read : Top Cylinder 60PSI [dry], 120PSI [wet]. Bottom Cylinder 60PSI [dry], 110PSI [wet]

I would appreciate the Forum's suggestions, please.

Also could you advise on the following.
1. The recommended compression value in either PSI or Kg/cm2 for this motor ???.
2. The specification has the Displacement at 8.84 Cu. Inches or 145 Cu. cm. Does this relate to compression ???.
3. Also looking for a website that has a "1966. 6HP Johnson Outboard Tune Up / Servicing Procedures", any suggestions ???.

Looking forward to your assistance, thank you. my email address is < letby@talent.com.au >
Jack Letby. Sydney.

 

[Saskatoon2005]

Re: Hard To Start : 1966, 6HP Johnson Engine.

Lubrication, Maintenance and Tune-up for 1966, 6HP johnson Engine

Lubrication for 1964-1972
a) Thoroughly mix one pint of Johnson or Evinrude 50/1 Lubricant with each 6 gallons of gasoline in your fuel tank. This provides the recommended 50:1 mixture.
b) Operation in Canada requires mixing one U.S. pint of Johnson or Evinrude 50/1 Lubricant to each 5 imperial gallons of gasoline in the fuel tank.

CAUTION: There are a number of oil products on the market which specify use at 100:1. They are NOT BIA-TC-W approved and should not be used.

Do not exceed a 50:1 (1964-1972) ratio.

 

[Saskatoon2005]

Re: Hard To Start : 1966, 6HP Johnson Engine.

Lower Drive Unit Lubrication for 1966, 6 HP Johnson Engine.

Lower Unit Lubrication for 4-125HP models.
1) Place a suitable container under the gearcase.

NOTE: If the lubricant is white or creamy in color or metallic particles are found in step 5, remove and disassemble the gearcase to determine and correct the cause of the problem.

2) Locate and remove the oil level plug and washer. See A, Figure 3 (typical).

CAUTION: The gearcase on models with a shift capability will have a philips head screw located beside the slotted drain/fill plug (Figure 4). The philips head screw secures the shift rod in place-do not remove it by mistake or it will be necessary to disassemble the gearcase to properly realign the components and reinstall the screw.

3) Locate and remove the drain/fill plug and washer. See B Figure 3 (typical).
4) Allow the lubricant to completely drain. If necessary, use a small suction pump to remove the lubricant.

NOTE: If the lubricant is creamy in color or metallic particles are found in step 5, remove and disassemble the gearcase to determine and correct the cause of the problem.

5) Wipe a small amount of lubricant on a finger and rub the finger and thumb together. Check for the presence of metallic particles in the lubricant. Note the color of the lubricant. A white or reamy color indicates water in the lubricant. Check the drain container for signs of water separation from the lubricant.
6) Inject OMC premium blen gearcase lubricant into the drain/fill plug hole until excess fluid flows out the oil level plug hole.
7) Drain about one fluid ounce of fluid to allow for lubricant expansion.
8)Install the oil level plug. remove the lubricant tube or nozzle from the drain/fill hole and install the drain/fill plug. Be sure the washers are in good condition are in good condition and properly positioned under the head of each plug so water will not leak past the threads into the housing. Tighten both plugs to 60-80 in-lb. (7-9 N.m).
9) Wipe any excess lubricant off the lower drive exterior.

 

[Saskatoon2005]

Re: Hard To Start : 1966, 6HP Johnson Engine.

Tune-up for 1966, 6HP Johnson Engine

The tune-up sequence recommended by Johnson and Evinrude includes the following:
a. Compression check.
b. Spark plug service.
c. Gearcase and water pump check.
d. Fuel system service.
e. Ignition system service.
f. Battery, starter motor ans solenoid check (if so equipped).
g. Wiring harness check.
h. Engine synchronization and adjustment.
i. Performance test (on boat).

So maybe you can be a little more specific as to what you want to know, or you can buy a manual...LOL!

 

[BF]

Re: Hard To Start : 1966, 6HP Johnson Engine.

1) If the compression is really 60 psi, that's pretty low, and could be the cause of the hard starting. Numbers around 100 and close to each other is what you should have. I don't think adding oil (wet test) and seeing the numbers go up tells you too much. It could be a bad head gasket, or worn rings...

There may be inaccuracy in cheap compression testers... escpecially if it's not the screw in kind. Normally the fact that the 2 values are similar to each other is more important than the actual value, but I think the cut-off for expecting a decent running engine is around 60. All my OB's always test between 90 and 115, so if something I tested had a compression of 60, I'd be convinced right away something was wrong. Does your compression gauge read higher on other engines?

2) Displacement doesn't determine compression.

 

[Jack Letby]

Re: Hard To Start : 1966, 6HP Johnson Engine.

Dear Saskatoon2005.
Thank you for your three replies to my 6hp Johnson starting problems.

I have taken your lubrication and servicing information on board, and will certainly adopt them.
Regards
Jack Letby.

 

[iwombat]

Re: Hard To Start : 1966, 6HP Johnson Engine.

If you tried to compression test with one spark plug still in, it's likely that you didn't spin the motor fast enough to get a good reading. The good news is that both readings are the same.

How did you determine that the spark was good?

 

[Jack Letby]

Re: Hard To Start : 1966, 6HP Johnson Engine.

Dear BF.
Thank you too, for your comments regarding the hard starting of my 6hp Johnson, I think you are much closer to my problem.

I purchased a new screw in type compression tester recently for Aus. $40.00 [made in Taiwan] it was the dearest of three in this shop, and hope the quality is OK for use in my shed at home.

The compression testers instructions suggested < If both cylinders have a low similar dry readings, proceed to a wet test. If the wet test show that the compression increases to nearly normal in both cylinders, then the rings, pistons and cylinders are in need of servicing >

I would like to hear your comments !!!.

My main motor is a 55HP Tohatsu and will conduct compression tests on that and a lawn mower today for comparison, and report back.

Once again thank you and will be in touch.
Regards
Jack Letby.

 

[Silvertip]

Re: Hard To Start : 1966, 6HP Johnson Engine.

Your question about displacement has nothing to do with compression. Displacement refers to the swept volume (the area covered by the top of a piston from the bottom of its stroke to the top) of each cylinder multiplied by the number of cylinders. Looked at another way, Its the amount of fluid measured in either cubic inches (CI) or cubic centimeters (CC) that it would take to fill the cylinders with each piston at the bottom of its stroke. In a 350 cubic inch Chevy V8 engine for example, it would take 43.75 cubic inches of fluid to fill one cylinder. Translated into cc's that same engine is a 5.7 liter. Just to get a little over the top with this, that same motor can be refered to as a 2.734 gallon motor. d

 

[itstippy]

Re: Hard To Start : 1966, 6HP Johnson Engine.

iwombat asks a good question: how did you determine that the spark is "good"? 1966 coils are immediately suspect. If they're original they're most likely junk. They age and crack regardless of run time. The spark on that motor should jump a 3/8 gap with a bright blue spark and a snap!. That's with the spark plug off and the lead wire hooked to a gap tester. Replacement coils are readily available and better than the originals.
60 psi compression is as low as you can go and have a decent running motor. Low compression will make it hard to start. If the motor's been an auxilliary and has low hours on it then the rings & walls are not likely worn. That takes many hours of use (but not many hours of misuse). A bad head gasket would usually only affect one cylinder. Your compression may return with a good decarb (Seafoam) treatment. It may be carboned up from its duty as an auxilliary and a decarb will free the rings. Also replace the rubber water pump impeller if it hasn't been. Like the coils the impeller gets old and brittle with just age. Like the coils the impeller is also readily available. Both are considered "consumables".

 

[Jack Letby]

Re: Hard To Start : 1966, 6HP Johnson Engine.

Dear BF, Iwombat, Silvertip, Itstipsy and Saskatoon2005.
You guys are just wonderfull [love your names] with you around I'm sure that the 6HP Johnson would not dare to give up.

I think that I have some positive news.

Prior to contacting the forum, I had made a telephone call to BRP Australia [Johnson Outboards] and received their return call a couple of hours ago.

He informed me that 1966 vintage 6hp Johnson's use's a lower compression and that mine should start on 60psi. He suggested to spray a little petrol into each spark plug hole, insert plugs and try the starter. Instant success was achieved, looks like I have to recheck the carburetor serviceing and float settings for petrol through to the combustion chamber. [I had recently installed a new carburetor kit]

Removed the petrol supply hose to the carby, pumped the petrol tank bulb, petrol gushes out.

My ignition spark testing was to earth each plug, pull the engine over and I observed a strong blue spark. Have you any ideas on making a spark tester please, I'd like to try ???. By the way I removed the fly wheel and replaced the coils about 1999.

To BF, my compression tester appears to work OK. The 55hp Tohatsu was 159psi and 150psi the motor specification rating is 125psi and my lawnmower went 70psi.

I wish Australia had a similar forum, you guys are great, thank you and thanks to Iboats for conducting this website.

Looking forward to further comments.
Regards
Jack Letby.

 

[ezeke]

Re: Hard To Start : 1966, 6HP Johnson Engine.

The spark tester they sell here at iboats might give you an idea of how to make a tester. Someone may still have a photo of one made from a piece of plywood.

I can attest to the fact that making them from a plastic cutting board from the kitchen will work, but will land you in the dog house, for sure.

http://www.iboats.com/mall/?keyword...=516790529&list_time=1170278717&view_id=38089

http://www.iboats.com/mall/image/vendor/16/big/38089.jpg

 

[Jack Letby]

Re: Hard To Start : 1966, 6HP Johnson Engine.

Dear Ezeke.
Thanks for the tip on spark testers, I have looked at Iboats website, its given me some ideas.

Also I have a perspex offcut from a plastic kitchen board, so no hassles from in the house.

You all have good suggestions, thanks.
Regards
Jack Letby.