1969 25HP johnson trouble

[302suawdust]

OK guys I am in need of allot of help here.

I picked up another 1969 25hp Johnson. I did all the normal stuff as it had not been ran in many many years. Here?s the list of what been done

Water pump impeller replaced
Ignition checked by cleaning and adjusting points (.020) and doing a spark test (great big 3/16? blue sparks on both cylinders no problem)
New plugs set to .030 and installed
Compression test both cylinders just over 100lbs
Carb cleaned and rebuilt by:
Disassembling and soaking for a few hours in carb cleaner
Blowing out with C/A
New float
Float adjusted to sit even with gasket on bowl
New Float pin and seat
Did the blow test to make sure float lets no air through when carb upside-down and air through when carb upright
Replaced to low speed needle valve plastic seal thingy (sorry couldn?t remember the correct name)
Adjusted the needle back one turn from full in
I did not remove the frost plug looking things on the carb (I may have to)
I cleaned the fuel pump and put in a rebuild kit
I am using new clean gas in a nearly new tank with a new fuel line and bulb

Now for the fun part
When I go to start it I pump the bulb until it is nice and firm. No fuel seems to escape past the float chamber into the barrel at this point (I think that?s a good thing)
I choke it and give it a pull ro two and it may or may not sputter a few times but it won?t stay running sometimes it backfires mildly.
The carb spits quite a bit of gas out of the barrel at this point. Also the choke butterfly seems to move quite wildly open and closed when it does fire(I think the springs are good as I compared it to another one and they seem the same)
The plugs do not seem overly wet after trying to start it.

I am starting to lean towards my own conclusion as to what is going on here but my experience is very limited with outboards so I would be grateful for anybody else?s insight as to what may be going on here.

Also my carb kit came with 3 little black O rings about ?? or so and a gasket that does not fit anywhere on my carb?. (what is up with that?) More importantly what am I missing?

Cheers,
Ian

 

[eavega]

Re: 1969 25HP johnson trouble

Hi

I noticed something missing in your start procedure; are you advancing the throttle to the proper position? I know that on my '67 20 HP Johnson, the "Start" mark is just a bit off from where the motor will start.

Also, make sure that the motor is not in gear when you try to start it. I'm not sure if it will or won't start in gear, I suspect it won't.

 

[alangf]

Re: 1969 25HP johnson trouble

My experience (over 50 years) with low speed needles is that the best preset is 2 1/2 turns back from closed. If it is initially set too lean it will result in the engine spitting back (sometimes called sneezing or coughing). The fluttering choke butterfly sounds like you may have a chipped or broken reed valve. These are mounted on a plate behind the piece the carburetor mounts to. It is a simple disassembly but you will need two gaskets in addition to the carb gasket.

 

[302suawdust]

Re: 1969 25HP Johnson trouble

Re: 1969 25HP Johnson trouble

Thanks,
I have been fearing that it may be a reed issue. Mostly because it is a pain in the butt for me to get the gaskets... but I can get them.

Anyway here is my plan for tonight. I am going to recheck the compression then I am going to pull the flywheel again just to make sure I did not sheer the key during my fumbling trying to get it started. Then I am going to try to start it one more time with the low speed needle backed out 2.5 turns. If that fails I will dig into the reeds....... Unless anybody else chips in with some other advice.

Cheers,
Ian

 

[302suawdust]

Re: 1969 25HP johnson trouble

Ok I am really stumped now. I checked the reeds they are fine in fact I would go so far as to say they are perfect. I rechecked to compression 106 on the bottom and 110 on top. I get great spark with a spark gap tester and I pulled both plugs and watched them spark by holding them against the block as well to make sure that I did not have a bad plug (I did grab some new plugs this AM as well that I will replace the old ones with just cause I can). I pulled me a timing issue. It was fine so it was replaced and re torqued. I verified the correct plug was firing when the matching piston was the flywheel again to make really sure the key was not sheared givingnear TDC

I am a little curious about the "start up procedure" I have never really done anything specific to start an outboard. I make sure it is not in gear (as my wife like to say it is in park ) I prime the bulb till firm. I advance the throttle just a hair choke it and pull away. On my other 25 it will start right up. However I will take any advice at this point so please let it fly.

I know the carb is getting fuel as after a few pulls it is dripping out of the barrel. I can not blow air past the float when I invert the carb (off the engine) so I am sure the float and valve is working correctly.

What am I missing. Any Ideas would be helpful even if they seem a little far fetched. I am at a total loss with this one.

 

[BF]

Re: 1969 25HP johnson trouble

I have a 1970 25 hp... I can add a couple comments about your start procedure. It might take more than just a "hair" of throttle... As someone said before, put it in the "start" range which should be something like 30-40% open.

Also, on my 25, with the low speed adjusted properly, procedure is prime until bulb is firm, make sure it's in N and throttle is set properly, pull choke out, pull rope 2 or 3 times. On the 2nd or 3rd pull, motor will fire, but usually die out within a second or so, (faster than I can reach down and push the choke in). Then I push the choke in, and it starts again on the next pull (with no choke), it may or may not require a quick "blip" (in and out) of the choke to keep it running... On mine there is no "1/2" choke it's either full choke, or no choke.

If I try and drive away from the dock within about 30 seconds from cold startup, my motor acts like it's on the lean side... it'll bog down and probably stall on throttle up. This can be countered by adjusting the idle mixture towards "rich" a bit until it warms up, or just letting it run at the dock for a minute or two before heading out.

So, on mine it is very easy to flood it, if you continue to pull try and start it with the choke out after the first time it fires. It appears (?) that my motor has a fine line between flooding and stalling from being lean when it is cold. It never requires choke to start if it is within an hour or so of being run. You're probably out a bit with your initial needle valve setting (which is normal... you'll have to tweak it once you can get it running)

I'd re-try starting yours with more throttle, and being careful about potentially flooding it.

Alternatively, you can squirt some premix (gas/oil mix) into the carb to get it running... this will bypass the idle circuit in the carb.

BTW, you do have the lower unit in a water filled barrel or trash can, right? The main water pickup on these motors is in the front edge of the little exhaust "fin" behind the prop, so the muff things don't work.

good luck.

 

[302suawdust]

Re: 1969 25HP Johnson trouble

Re: 1969 25HP Johnson trouble

Thanks,
I will try to advance the throttle a little more I don't see any markings anywhere as to how far ahead to go. Should I move it forward (the throttle that is) until I hit the neutral stop point? I will have a look in the service book I have. Maybe I missed some important startup info. Oh I should point out this motor is set up for console steering not a tiller. There is no tiller handle. But I have the control cables hooked up.

I do have it in a barrel full of water. As you pointed out muffs do not work on this motor due to the placement of the intake.

Ian

 

[BF]

Re: 1969 25HP johnson trouble

yes, if you're at the N throttle stop, that's the max fast idle in N. (usually ~ 1/2 throttle)... A little less than that would be the "start" position. If you've got the throttle turned down too low (to the normal "idle" range) it will likely be v. hard to start... FYI, the idle speed is completely controlled by timing advance... not the carb linkage. The carb butterfly doesn't start to open until later (you can see the roller on that little cam).

seems wrong to me that your choke is fluttering... are you sure it's functioning OK? There was a problem with mine when I bought it. One of the springs was worn 1/2 way through so would sometimes "catch". So, the choke wouldn't close all the time when the knob was pulled. (was the cause of an intermittent hard starting problem).... once the choke was fixed, it became very predictable.

 

[rjezuit]

Re: 1969 25HP johnson trouble

Here's a wild guess, the correct spark plug wire on the correct cylinder. If they are firing where they should not be it may cause a cough or backfire, kind of like firing when the intake port is exposed. Rick

 

[302suawdust]

Re: 1969 25HP johnson trouble

GOT IT

Turns out the choke override spring was busted right in the middle of the coil. Mostly the choke seemed to operate normally but of course this would allow it to flutter wildly when the engine was running with the choke on (or at least trying to run). I did a "duct tape and barb-wire" fix on it to get it to work correctly and now it will start on the second pull when cold and first pull when warm. I ordered a new choke override spring this morning so I should get that next week. Thanks everyone for your help. I was really running out of ideas. It is great to put new life back in an old engine..... now that this one is all good I am wishing I had onther one to work on

Cheers
Ian

 

[rjezuit]

Re: 1969 25HP johnson trouble

Old engine? That ones a baby compared to some of them on this board. Hardly even broken in yet. Glad you found the problem, many times the easy problems are the easy ones to miss. Rick

 

[BF]

Re: 1969 25HP johnson trouble

good to hear the success! FYI, on mine when the choke spring was worn, I was able to carefully remove it and straighten a bend or two out of it and reinstall it... it worked fine until I found a replacement one.... maybe won't work if it's broken in the middle...

congrat's... feels good to track down a prob, doesn't it!