Prop, or Engine Issue?

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,666
The difference is that you see them as a “classic” motor from your past. Later generation(s) see them as “vintage” (nice way of saying old) motors, that are inexpensive to buy. That combination makes them disposable should something go wrong.

Bear in mind that vocational training in public schools was discontinued almost 50 years ago now. That’s two generations that don’t know the difference between a carb and a distributor and don’t care. Not that they need to know given that both components were replaced with new technology prior to their birth.
I was in high school in the mid-late '50'a and we had a "vocational "wing" on the campus. Taught all the things that you could do locally to earn a living if you didn't go to college....which weren't available like they are today, Jr. College in particular....big loss for us back then.
My favorite class of all was Mechanical Drawing; part of that wing. I found it extremely interesting and it helped me immensely in my education and career later in life......the second best, not my favorite per se, but I needed an elective and thought that typing would work as I diddled a bit with typewriters (Royal for one, used in class). As a result of selecting that class, I found a wife of 49 years (deceased) and when computers came out, I was prepared for their keyboards....whatta deal.
 

wdirnbeck

Seaman Apprentice
Joined
Jun 5, 2022
Messages
42
When everything was running well I am happy to report I was getting 4900 rpm with 3 people and the 13 1/2” x 15 prop.

Post the actual compression test values.----Should be around 140 PSI.

I see now from the Top Secret folder in Johnson outboard repair that I did the compression test wrong. My engine was cold and I cranked it from the ignition. I have developed a spark issue so I wasn’t able to warm up the engine so I will be starting another thread in the appropriate forum.

My compression values just FYI:
Top- 80 psi
Mid- 75
Bottom- 70-75

Thanks all.
 

airshot

Vice Admiral
Joined
Jul 22, 2008
Messages
5,080
When everything was running well I am happy to report I was getting 4900 rpm with 3 people and the 13 1/2” x 15 prop.



I see now from the Top Secret folder in Johnson outboard repair that I did the compression test wrong. My engine was cold and I cranked it from the ignition. I have developed a spark issue so I wasn’t able to warm up the engine so I will be starting another thread in the appropriate forum.

My compression values just FYI:
Top- 80 psi
Mid- 75
Bottom- 70-75

Thanks all.
Ouch, even cold and dry, those are low numbers. Time for another engine ?
 

wdirnbeck

Seaman Apprentice
Joined
Jun 5, 2022
Messages
42
Ouch, even cold and dry, those are low numbers. Time for another engine ?

If fixing my spark issue has it running well enough to get around the lake then I guess a rebuild might be in order this winter.
 

jimmbo

Supreme Mariner
Joined
May 24, 2004
Messages
13,446
I see now from the Top Secret folder in Johnson outboard repair that I did the compression test wrong. My engine was cold and I cranked it from the ignition. I have developed a spark issue so I wasn’t able to warm up the engine so I will be starting another thread in the appropriate forum.

My compression values just FYI:
Top- 80 psi
Mid- 75
Bottom- 70-75
Another Compression Gauge might yield/provide better info. As stated Prior, those Numbers are slightly over 50% of what would be expected....

Careful about a another Thread, as running 2 Open Threads by the same Person about the same Motor, can get complicated to follow...
 

wdirnbeck

Seaman Apprentice
Joined
Jun 5, 2022
Messages
42
Resolved the spark issue with a new power pack and running at 5100 rpm on the tiny tach under load. All seems to be well in my world for now but I’ll still probably have a look at the cylinders here soon to see what there is to see.
 

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,666
Really-----Every big JOHNSON since about 1962 had a temperature alarm !!
I don't know if you would classify the 70 HP Johnson 3 cylinder Looper a large engine. If that engine had one the PO nor I were aware of it......like I said, I knew little about outboards back then and had no manuals.
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
37,818
Big Johnson refers to the models available in say 1963.-----A 75 HP motor was a " really big " outboard then !!!
 

airshot

Vice Admiral
Joined
Jul 22, 2008
Messages
5,080
Big Johnson refers to the models available in say 1963.-----A 75 HP motor was a " really big " outboard then !!!
I can remember back in those days, my uncle bought a new outboard....the biggest and newest on the market. Can't recall whether 50 or 75 hp, but had a big 4 barrel carb in the front of the V4 engine....man did that thing suck down the fuel !!
 

jimmbo

Supreme Mariner
Joined
May 24, 2004
Messages
13,446
The only OMC Outboards that had a 4 Barrel Carb were the 64-65 90hp and the 66-68 100hp, the other V4s up till 68 had a 2bbl Carb

The engines that had the 4bbl were actually easier on gas per HP than the 2bbl Motors
 

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,666
Back in those days there was no XXX.com. BUT, the motors all came with an owner's manual which detailed everything you needed to know. PLUS, the dealers back them had been in bizness since the late 1940's, and all you had to do was ask.
Well sir, I didn't get a manual from the owner, never thought about it, and didn't frequent dealers. I was busy helping my wife raise 4 kids, going to school, and working a stressful job....that paid well. On the boat, you get home from church, change clothes, load up the kids and gear, stop by the chicken joint, then the gas station and head off to the lake. Other than tearing up OEM aluminum props on my new 1972 Johnson 125 (which the SST solved when it came out in 1973), that's the only problem I had with my engines over a lotta years.
 

JimS123

Fleet Admiral
Joined
Jul 27, 2007
Messages
8,162
Well sir, I didn't get a manual from the owner, never thought about it, and didn't frequent dealers. I was busy helping my wife raise 4 kids, going to school, and working a stressful job....that paid well. On the boat, you get home from church, change clothes, load up the kids and gear, stop by the chicken joint, then the gas station and head off to the lake. Other than tearing up OEM aluminum props on my new 1972 Johnson 125 (which the SST solved when it came out in 1973), that's the only problem I had with my engines over a lotta years.
Your story parallels mine in many ways. Except only 2 kids and I was on the road 50% of the time.

My only "bad" engine was a '68 Evinrude Lark that kept burning out the electrical system because of a bad design. The only second hand motor I bought without a manual was in later years, and I found a copy on EBay.

I am amazed about the current Enertia prop performance, but back in the day that 'ole SST was a big step forward.
 

jimmbo

Supreme Mariner
Joined
May 24, 2004
Messages
13,446
My only "bad" engine was a '68 Evinrude Lark that kept burning out the electrical system because of a bad design. The only second hand motor I bought without a manual was in later years, and I found a copy on EBay.
We had the 63 Johnson Electramatic, and it never gave any Electrical System Problems. Granted it didn't have any Electrical Circuit for the Choke.
In 63 the Starter Solenoid and Charging Regulator for the Generator were in a Junction Box in the Bilge. By 68 I think all that stuff was under the Engine Cowl

I am amazed about the current Enertia prop performance, but back in the day that 'ole SST was a big step forward.
The Enertia is Great Prop, for a lot, but not all Applications. I have been running one for over 18 years
 
Last edited:

JimS123

Fleet Admiral
Joined
Jul 27, 2007
Messages
8,162
What was the " bad design " on the 68 LARK ??
The wiring that ran down to the Selectric Shift lower unit were routed alongside the exhaust tube. Within a year they fried from the heat, leaving me stuck in neutral. I call that a "Design Flaw".

It was covered under warranty, and as they were working on the engine the dealer called me in to show me that they put extra insulation in and routed them as far away as possible. Within another year it failed again. This time I DID have reverse gear left, but it stranded me within sight of Niagara Falls. The 5 minute trip to the launch ramp took 3 hours going backwards. Fortunately the gas tank was full.

That sucker was back at the dealer the next day, and I traded it in on a 1970 Triumph, also Selectric. But the dealer assured me that the design was different and in case of a failure it would default to forward. I owned that motor for 8 years
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
37,818
I worked at a dealer back them---Worked on many electramatics ( wonderful design ) in that shop.-----Never saw an issue with the wires.
 

JimS123

Fleet Admiral
Joined
Jul 27, 2007
Messages
8,162
I worked at a dealer back them---Worked on many electramatics ( wonderful design ) in that shop.-----Never saw an issue with the wires.
Is an Electramatic the same design as a Selectric?

When I bought the Lark I was trying to decide between the 'Rude and the Johnny. Both were the same HP. I ended up with the "Rude because I thought the push buttons were a neat feature.
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
37,818
Selectric and Electramatic are EXACTLY the same.----Johnson used a switch in the control box.----Evinrude used push buttons.----The rest is all the same except for paint color and cowling cosmetics.
 

JimS123

Fleet Admiral
Joined
Jul 27, 2007
Messages
8,162
Selectric and Electramatic are EXACTLY the same.----Johnson used a switch in the control box.----Evinrude used push buttons.----The rest is all the same except for paint color and cowling cosmetics.
I guess you can never trust what a dealer tells you. Or, maybe my engine was one of the few that DID self-destruct.

See post #7:

 
Last edited:
Top