56 Johnson 15 hp hard to start.

[acwd]

is the nozzle well gasket that you are talking about the one between the top and float bowl that fits around the nozzle? If so its there. The kit is a OMC kit from marine engine .com. I did some more experimenting yesterday afternoon. I let it sit with tank pressure all afternoon til about 5. Approx. 4 hours. Walked over pulled the choke and gave her a pull fired off. WTF! So I disconnected the fuel line and run it dry. Reconnected the line and pushed the primer button 4 or 5 times. Then pulled my *** off then it finally started. I dont know if its me or the motor! It has sit all night with pressure so I will see how it starts this morning. I do know this is how the high and low needles are set right now. The high one is about a half a round out and the low is two rounds out. So how many pumps should does the primer button need? Also according to the starting instructions in the book I found online it said to choke it to kill it? I dont do that. Could that have a bearing on this?

Steve

 

[Pappy]

The low speed sounds like it is too far out. When it starts again start turning it in until the engine speeds up by itself then either spits lean or RPM starts to drop off then back out around 1/4 turn or a little more. You may want to back the high speed out to around 3/4 turn while doing this. The high speed can then be tuned and finally the low speed may require a minor "trim".
If you have an OMC kit there should have been several packing washers in there. I use two per needle and one nylon one. The nylon one is placed last so it will be a bearing between the packings and the jam nut.
As far as how many pumps? All you are doing is filling the lines, filter and fuel bowl until the needle closes the fuel off. Once the bowl is full any additional pumping is doing nothing.

 

[acwd]

I took the carb back off and changed the packing around the needles. I didnt have it in there right and added some packing washers. I checked the float level and dropped it some it looked a little high. Put it back together and primed it up and pulled the rope and fired off. Adjusted the needles like you said. It wouldnt idle at all so it came back out to about 2 turns out. under that it sneezes and dies. and the high speed one comes out about the same as before. I dont know what is going on. Going to run it on the lake today and see how it does. I am pretty good with motors and such but this one is eating my lunch!

Steve

 

[acwd]

Well took it to the lake yesterday. Didnt think I was ever going to get it started. But finally did. Adjusted everything in gear. High speed needle is about 3/4 out and low speed is 1 1/2 out. Still a bear to start. I did get premium fuel at Marathon to see if that helped or not. I dont know what else to do I am at a loss. Anybody have anymore ideas? I am tired of wasting time and money on it.

Steve

 

[bbstacker1]

Just curious where do you have the throttle set at when you are trying to start it. If you are going by the band on the tiller and setting it at start try opening it up a little more. I have an AD-11, 7.5 hp that if you put it on start you will never get it started when cold, you have to open it right up, after it starts and is warm it will then start easily at the start setting.

 

[Pappy]

If your idle needle is set at 1.5 turns or so that may indicate an air leak. An air leak also will create a hard starting situation as the leak is more detrimental the slower the engine is running. Very evident at cranking. Think of an air leak as kind of a small fixed air jet. Faster the engine is turning the less effective it becomes.
You can try spraying some gas around the crankcase seams and various fittings on the engine and see if you can make a difference or you can also turn on a torch without lighting it and guide it around while the engine is idling and see what you get. I have always tried to be careful when I do these two checks because of the points ignition but apparently the flywheel rotation keeps the fumes out pretty well. BE careful anyway....................
Another check would be to run compressed air at a very low pressure into the cylinder and crankcase and see if it is leaking. You can do this at the carb flange area and just hold your hand over the air nozzle and intake. The piston on each cylinder being tested has to have the ports closed to pressurize that half of the cylinder and crankcase. Soap and water will show you a leak.
You can also use soap and water on any entry point into the cylinder and crankcase while the engine is running and it should show you a leak in all but the upper main area or lower main area. Spray bottle will work for this.

 

[acwd]

I will have to try that some time.

Steve

 

[acwd]

Ok today I got the motor out and put her in the barrel. After cussing and pulling my arm off finally it started. Sprayed every joint with soap and water only bubble seen was on the exhaust cover and it was a tiny one. So I sprayed every joint with a little carb cleaner. No change in the way it ran. I did notice this today. After the third pull there was gas running out the carb but you cant get it to hit unless you have it choked. So after all that I did testing. I decided to pull the plug wires one at a time. she ran on one cylinder. Bottom one was not as strong as the top. So they are both firing. I did notice the top bearing is a little loose. Could that change the points gap enough to make it act this way? Could the reed valves be sticking or not closing tight enough to make it act this way? So tired of messing with it. Ready to send it on down the road.

Steve

 

[acwd]

Ok I think I found the problem. I found the gas leak. It was the packing nut on the high speed needle. Tightened them both the packing nuts up. Fixed the gas leak. Helped a little. Next I gapped the plugs wider, helped it a little more. So got to looking at the linkage from the roller to the carb. Seems it got alot of wear. So I adjusted the cam follower plate out. BINGO! Changed it alot. IT will sit all night. Go out in the morning, pull the choke and fires off the first pull! This morning first pull fires off. So I dont know if that was all of it or a combo of different things. But it starts and runs better than it ever has. The roller has some wear on it. Probably needs replaced.

Steve

 

[Pappy]

If the top bearing is loose it is worth checking. But, at this point you have it running so run it and enjoy it for a while.
When you feel like it go ahead and split the cyl. and crankcase and do the upper and lower seals, etc.

 

[satx78247]

To ALL,

IF you wish to become a "vintage OMC addict" as I am, go buy yourself a copy of: CHEAP OUTBOARDS: THE BEGINNER'S GUIDE TO MAKING AN OLD MOTOR RUN FOREVER by Max E. Wawrzyniak III & take his wise advice to buy a 1955-70 BROOKLURE, EVINRUDE, GALE, JOHNSON, SEA BEE or SEA KING outboard (from a "community bulletin board", AOMCI meet, estate/garage sale or other similar place), then purchase all your parts from SIERRA, which are sold by NAPA Auto Parts stores & other places.
(NO, I don't work for him & I own NO stock in NAPA Stores, either; I'm just one of his many fans. - Fwiw, Amazon.com often has the books at a "discounted price".)

Fwiw, I've always owned at least one or two OMC "BigTwin" outboards in all the years since I was since I was 14YO in 1960.
(At times, I've had over 25 BigTwins at a time. - Fwiw, my first BigTwin was a 1957 Evinrude 35HP.)

I always replace the coils, points, spark plugs, condensers, spark plug wires, water-pump impeller & rebuild the carb(s) on ALL of the old OMC OB motors that I acquire, as that saves "aggravation" & "days lost to fishing". - Doing that costs about 80-100 bucks per motor, if you shop carefully & will result in you're having an "as new" ignition system & an OB that pumps water FINE.
(BigTwins are so simple that you need NOT be a "mechanic" to work on one. - A few wrenches,screwdrivers, a hammer, lubricants, soap, etc. AND some ordinary COOMONSENSE will do you FINE to "fix up" most any older OMC motor.)

Note: I have a second cousin who makes his living as a commercial trot-liner and he has/runs the same pair of 1965 OMC 40HP outboards daily, that he bought back then. = BigTwin OBs are so "OVER-engineered" that I've never seen one that was "worn-out in service", though I've seen many that were "abused to death".

just my opinion, satx

 

[SumDumGuy]

I never knew there was an option to not buying a vintage motor. :shock: :wink:

While we're plugging....

I have been working on restoring a '53 15hp Evinrude. It was missing quite a few parts. As you can imagine the parts for a 1950's motor are no longer manufactured.
I ran across the site Gano's Outboards and to my surprise Mr Gano has/had everything I needed to get this motor back in shape.
He is also a very good guy to deal with and goes out of his way to get required parts, and the parts are a lot better price than other places (eg Ebay).
So, if your looking for vintage OMC stuff get in touch with Dan.

Dan Gano
https://ganotech.com/

 

[SumDumGuy]

And everything satx stated about these old motors is true. Easy to work on, and with a little maintenance will probably outlive all of us.
One strange thing about the older vintage motors though, they are made out of 99+% of this stuff called metal. I guess they used to use that stuff before they started mining plastics.

 

[satx78247]

SumDumGuy,

THANK YOU for Mr. Gano's web address. - Didn't know about that one.

I didn't say earlier but my FAVORITE BigTwin is the last couple of years (1962-63) of the 40HP GALE DELUXE ELECTRICS or the same vintage SEA KINGS, that were sold by Montgomery Ward. - The Gales/Sea Kings just seem to be a little BETTER/TOUGHER outboards, even though almost all of their parts are the same as Evinrude & Johnson parts.
Also, they are considered by many "outboard collectors" to be an "off brand" & thus CHEAP to buy/maintain. Gale OB motors were sold by hardware/sporting goods/discount stores. Evinrude & Johnson OB were sold only at franchised marine dealers
(I am well-known by friends to LIKE "cheap". = In point of fact, IF you ask for a part to fit a Gale, you may well be quoted a price that is LESS than the identical part for an Evinrude or Johnson. ======> That's a "deep, dark secret" - Don't tell a soul!!)

Let me give you just one example: in late 2011 I went to a local AOMCI "dry meet" that was held at a local community college parking lot. While "shopping" for another OMC 40 horse "long-foot", I saw a 1963 Evinrude for 200.oo, a 1965 Johnson for 250.oo and a 1962 Gale DE for 175.oo. ALL of the OB were in relatively good condition, had acceptable compression, had the controls/cables and all were electric start 20" shaft.
(The Gale had a good used 6 gallon gas tank. The Evinrude & Johnson did not include tanks.)
Can readers guess which OB that I bought??
(I paid 140.oo for the Gale after some "dickering".)

After replacing all "the usual suspects" at a cost of 86.oo + tax and buying 2 "rattle cans" of spray paint, I have LESS than 250.oo in a GREAT-running/GOOD-looking 40HP OB, that will likely outlast me. - What's NOT to like??

just my OPINIONS, satx