1969 Johnson 20HP hard to pull recoil starter

[plessm]

I just bought a 1969 Johnson 20HP that has recoil start. It is very hard to pull. Compression tests show between 115 and 120 PSI for both cylinders. I got on this forum, which is great by the way, and found some threads about needing the recoil rope to be the right diameter and length. Something about the mechanical advantage of the rope length, the oblong pulley, and the timing.

I measured my rope and was excited to see it was only around 58 inches, and the timing mark was off. I went to my local OMC dealer and they ordered me the correct diameter and length rope, I believe it's 70-3/16". Anyway, I removed the old rope, put the new one on, adjusted it so the arrow on the recoil housing lines up within the spec lines on the pulley. Bolted it back up, it didn't seem to make any difference on the pull effort.

I was beginning to think I was just a sis or something, but I went out last weekend with my cousin and he has a 30 HP Johnson pull start, early 90's model. I could pull that thing left handed, no footing leverage, leaned over at a bad angle. It was so smooth and easy to pull and start.

I'm also making sure I'm in neutral when pulling. I've read other posts here about hard to pull motors, and one even said they have this exact engine and their 12 year old daughter can start it. I've pulled the plugs out and it pulls smooth as silk, very easy. When I put one plug in, it gets pretty hard to pull, lots of compression, then with both plugs, it really fights against you.

I can get it started, but I'm young. I want my dad to be able to take the boat out when he wants, but I think he's going to have trouble pull starting it. I thought maybe it has carbon build up and I would de-carb it according to the FAQ here. I looked for some Sea Foam I think it's called at my local auto stores and couldn't seem to find it.

Any suggestions? Thanks a lot.

 

[tashasdaddy]

Re: 1969 Johnson 20HP hard to pull recoil starter

some of the smaller ones were harder to pull, than the larger, the old 35's had a compression release on them, the larger ones had a bigger flywheel for the recoil.

 

[jspringator]

Re: 1969 Johnson 20HP hard to pull recoil starter

I just bought a 1975 25 horse Evinrude, which is almost certainly the same block as a 1969 20 horse, and it never occured to me it would be hard to start. I'll let you know how it pulls when it comes in.

 

[F_R]

Re: 1969 Johnson 20HP hard to pull recoil starter

Anybody here believe in reincarnation? Sounds like the same story we beat to death awhile back. It never was solved, was it??

Anyway, the rope and arrow and all that stuff has nothing to do with it. That only affects how far the rope comes out before engaging the flywheel.

I was convinced that guy had the wrong starter or something. But now am not so sure. Have no other idea what is going on here.

 

[iwombat]

Re: 1969 Johnson 20HP hard to pull recoil starter

I remember that discussion. I also recall something about an eccentric pulley and the need to line the timing marks up to get the best leverage on the compression cycle. Of course, I could be inventing all that in my head.

 

[plessm]

Re: 1969 Johnson 20HP hard to pull recoil starter

I remember that discussion. I also recall something about an eccentric pulley and the need to line the timing marks up to get the best leverage on the compression cycle. Of course, I could be inventing all that in my head.

Yes, I searched and found this thread a couple weeks ago. I never did see a conclusion to it, other than I needed the 70-3/16" rope to have the optimum leverage and timing, and to have the arrow lined up between the two lines on the pulley. I was hoping this was going to solve my problem.

The guy who was posting before said when he put the right length rope on it made some difference, but was still hard to pull. I didn't notice any difference. I've been watching for a starter motor with the bracket I need off a 25 HP motor to retrofit. I know my dad isn't going to be able to start this motor without some assistance.

 

[bgbass.1]

Re: 1969 Johnson 20HP hard to pull recoil starter

A friend had the same problem ran it for 2 years that way had good compression ran great when you pulled starter rope needed 2 hands ended up being head gasket no good. Just be carful after you replace it he ended up on his back side with rope in hand he pulled 2 hands only needed 1 pulled much easier.

 

[plessm]

Re: 1969 Johnson 20HP hard to pull recoil starter

A friend had the same problem ran it for 2 years that way had good compression ran great when you pulled starter rope needed 2 hands ended up being head gasket no good. Just be carful after you replace it he ended up on his back side with rope in hand he pulled 2 hands only needed 1 pulled much easier.

I'm wondering how the head gasket can affect rope pull? Seems to me if the head gasket was bad, it would have less compression and easier to pull?

Head gasket is cheap and easy to replace though. If that's the ticket, then I'll be all over it.

 

[wbeaton]

Re: 1969 Johnson 20HP hard to pull recoil starter

A friend had the same problem...ended up being head gasket no good.

Can you elaborate on that? I can't figure out how that would matter.

I find those motors can be hard to pull start if they don't start firing right away. Does the rewind starter get hot when you are running?

 

[plessm]

Re: 1969 Johnson 20HP hard to pull recoil starter

Does the rewind starter get hot when you are running?

It warms up as it is bolted to the powerhead in 3 spots, so heat transfer warms the aluminum. It is a breeze to pull without spark plugs in the cylinders, hot or cold, so I don't believe it is the recoil mechanism causing it to be hard to pull.

When pulling the rope it definitely is hard to pull right on the compression strokes of both cylinders. The rope "pops" and gets hard right on the compression. That couple of inches between compression, it pulls easy.

It needs a two handed pull like the guy above says, and a foot on the transom, and a good lean away from the motor as you crank it over.

 

[plessm]

Re: 1969 Johnson 20HP hard to pull recoil starter

...ended up being head gasket no good. Just be carful after you replace it he ended up on his back side with rope in hand he pulled 2 hands only needed 1 pulled much easier.

Oh, maybe the new head gasket was thicker, lowering compression? That's an idea. Maybe mine has an incorrect head gasket.

 

[F_R]

Re: 1969 Johnson 20HP hard to pull recoil starter

Let's put the recoil rope issue to bed, If I have the words to explain it.

1. The rope pulley is oval shaped so that it is effectively bigger for more leverage when going over compression, and smaller for faster spin between compressions.

2. There is only one pawl on the pulley to engage the flywheel

3. There are only two notches on each side of the flywheel. One would be enough, but they give two to get a better chance of not missing it and having to go clear around to the other side before grabbing. The notches are positioned such that the larger pulley diameter coincides with the compression.

4. No matter how long the rope, the pawl will grab the flywheel on one side or the other. Either side gives the mechanical advantage to make it easier to pull over compression.

5. Whether the rope is ten feet long or one foot, the pawl will still grab the flywheel in the correct(only available) spot(s).

6. The rope length is spec'd so that the pawl will be extended and grab the first flywheel notch that it comes to. If it should miss that one it will grab the second one. If the rope is the wrong length it will pull out further before grabbing a notch, in other words it may have to go clear around to the other side of the flywheel before grabbing a notch. But even if it does do that, the relationship between the pawl, flywheel, compression and pulley shape remains the same.

I hope this is understandable.
Frank

 

[F_R]

Re: 1969 Johnson 20HP hard to pull recoil starter

Does that powerhead show signs of ever having been disassembled? 18, 20, and 25hp motors use different combinations of pistons and cylinder heads. Maybe somebody has switched pistons or head to get higher compression, hoping for more power.

 

[plessm]

Re: 1969 Johnson 20HP hard to pull recoil starter

Let's put the recoil rope issue to bed, If I have the words to explain it.

1. The rope pulley is oval shaped so that it is effectively bigger for more leverage when going over compression, and smaller for faster spin between compressions.

2. There is only one pawl on the pulley to engage the flywheel

3. There are only two notches on each side of the flywheel. One would be enough, but they give two to get a better chance of not missing it and having to go clear around to the other side before grabbing. The notches are positioned such that the larger pulley diameter coincides with the compression.

4. No matter how long the rope, the pawl will grab the flywheel on one side or the other. Either side gives the mechanical advantage to make it easier to pull over compression.

5. Whether the rope is ten feet long or one foot, the pawl will still grab the flywheel in the correct(only available) spot(s).

6. The rope length is spec'd so that the pawl will be extended and grab the first flywheel notch that it comes to. If it should miss that one it will grab the second one. If the rope is the wrong length it will pull out further before grabbing a notch, in other words it may have to go clear around to the other side of the flywheel before grabbing a notch. But even if it does do that, the relationship between the pawl, flywheel, compression and pulley shape remains the same.

I hope this is understandable.
Frank

Thanks, that makes sense. Rope length doesn't matter, I just lined up the arrow and the marks on the pulley to ensure I don't have to pull more rope out before starting to turn the engine over.

Any ideas on why it's so hard to pull? If this particular model was a two hand puller, that's fine by me, then I know nothing's wrong. But since someone else here posted their 12 year old daughter can start it, I'm thinking something's out of whack. I'd like to just pull start it and not have to spend extra money, time, and additional weight and battery trying to convert to electric start for my dad.

Thanks.

 

[plessm]

Re: 1969 Johnson 20HP hard to pull recoil starter

Does that powerhead show signs of ever having been disassembled? 18, 20, and 25hp motors use different combinations of pistons and cylinder heads. Maybe somebody has switched pistons or head to get higher compression, hoping for more power.

I'm not an expert, but the head bolts don't appear to have any marks on them. The powerhead seems to have the original paint.

I'm just wondering since this thing is 40 years old, maybe it's coked up with carbon enough that the compression is raised above normal.

Does anyone know what stock compression should be on this motor?

Thanks.

 

[wbeaton]

Re: 1969 Johnson 20HP hard to pull recoil starter

Your compression isn't the problem. Those numbers are fine.

Your recoil starter isn't the problem. I wondered if it was rubbing on the flywheel nut because someone didn't re-install the flywheel or magneto properly.

The only other things that would make it hard to pull over are internal to the powerhead or lower unit. However, I haven't seen a motor that was that hard to pull and still run. I don't think there is anything else you can do without some disassembly. Try removing the lower unit and see if its still hard to pull. If it is then the problem must be in the powerhead.


You haven't by chance replaced any exhaust or powerhead gaskets have you?

 

[F_R]

Re: 1969 Johnson 20HP hard to pull recoil starter

Look at the parting line where the crankcase meets the cylinder. Do you see sealer squeeze-out? When built, the powerhead was painted after assembly was complete, so the sealer would be painted too. However, a good rebuilder may have painted it after work was completed too.

 

[samo_ott]

Re: 1969 Johnson 20HP hard to pull recoil starter

Yeah, I know you dont want to hear this but my 110 lb wife can pull start my 18 and start it on the first pull!

 

[tashasdaddy]

Re: 1969 Johnson 20HP hard to pull recoil starter

my 55 15hp was a 2 hander, my 58 35hp with the compression release is still a 2 hander.

 

[F_R]

Re: 1969 Johnson 20HP hard to pull recoil starter

Samo's wife should be able to start a 20hp too. And I don't even know her. There is something fishy about that 20.