73 Johnson 9.5 rough low speed

[cr9c1]

Re: 73 Johnson 9.5 rough low speed

I think you may be on to something with stuck reeds or a problem with the reeds. I did some experimenting tonight (We wont get into what) but it indicated a stuck reed. Not sure if I got it free'd up or not. I really don't want to have to split the halves apart. I may try the decarb trick with Seafoam. Seafoam is pretty good at cleaning up gunk/varnish/etc.

I had asked this question in an earlier post but never got a real definite answer. What does napa not list a carb rebuild kit for these 9.5s? They only list 8 and 9.9HP engines. And I dont see one on the iboats site either.

Carb cleaner (The flammable type) around the intake area didn't yield any results either. I swapped a new fuel pump on to rule that out. No difference. The most definitive thing I found was the reeds. My testings indicated that cylinder #2's reeds were stuck open. However, neither plug #1 or #2 seemed any darker than the other. There is a lot of smoke associated with the rough running, almost like its getting too much fuel (Stuck reeds?)

 

[iwombat]

Re: 73 Johnson 9.5 rough low speed

Well, now that you have the reed plate out. Make sure you clean out those bronze fittings at the bottom too. I got my rebuild kit at sea-way.com. Johnyrude dealers should have them too.

Let's go back a bit though. In your first post you mentioned a complete carb rebuild. But, you're having a hard time getting a kit. Did you do a real rebuild or not? This sounds like a carb problem, but given the carb rebuild in the first post I went right over that.

 

[cr9c1]

Re: 73 Johnson 9.5 rough low speed

Nah, I didn't take the reed plate out. I did some redneck checking. Looked like the 2n'd cylinder reeds were leaking. I'm going to have to do the decarb before I take the engine case apart. Its such a detailed process. Im just thinking at this point its stuck reeds, and it may actually be fixed now. I have to try it on the lake, maybe tomorrow. Work has me pretty busy.

 

[iwombat]

Re: 73 Johnson 9.5 rough low speed

I snuck in an edit during your last post.

Please explain exactly what you did to the carbs. Let's try and eliminate that for real.

 

[Tcbounty]

Re: 73 Johnson 9.5 rough low speed

Hi ( New to this site )
I have had the same trouble with my 2ea. - 5 hp.evinrude my 9.5 johnson and a 10hp evinrude. It turned out to be the gas mix... You guys have covered everything . Hope i'm not intruding ( Just trying to help )
Harry...

 

[lmddmc]

Re: 73 Johnson 9.5 rough low speed

when you adjust the low speed jet does it change the idle speed at all. I still think its in the low speed circuit. Is this the low squatty 9.5 outboard
also when its running rough pull the choke on real slow and see if it starts smooth out

 

[cr9c1]

Re: 73 Johnson 9.5 rough low speed

Yes, its a "low squatty 9.5 outboard". I've totally completely cleaned the carb. There is no way its carbueration. I've already tried another carb and it made no difference whatsoever, and on the motor the good carb came from, ran like a champ. This is something else, whether it be the reeds or my fuel is just plain crappy, which will be confirmed coming right up.

The carb is functioning 100%. Completely cleaned, blown out with compressed air numerous times, soaked in carb cleaner, and blown out again, new rebuild kit + float + needle + all gaskets.

 

[iwombat]

Re: 73 Johnson 9.5 rough low speed

Okay, I'm convinced.

 

[cr9c1]

Re: 73 Johnson 9.5 rough low speed

Seafoam'd today, not much of a difference.. A little better. Still leaning towards fuel. Maybe I can get some fresh stuff in it tomorrow.

It acts like its dropping a cylinder but I've tried an entire other ignition system (coils, points, condensers) and it has brand new OMC spark plug wires and brand new Champion J6C plugs gapped .030. So I'm kinda at wits end. Maybe Im just going insane or something, I think it should run a lot better at low speed.

The spark plugs look the same, doesn't look like one cylinder is running richer than the other. I tried a new fuel pump too. The only thing I haven't done is tried a new set of plugs (again) and removed the reeds. I'm just having a hard time believing it could be any thing other than possibly plugs, reeds, or fuel.

 

[cr9c1]

Re: 73 Johnson 9.5 rough low speed

Well, seemed to run better on a leaner mixture of fuel. (More like 50:1 instead of what I had in the tank which was probably 24 or 32:1)

Run a lot smoother and it seems like most of the roughness went away. My next question, seems how I believe I may have conquered this problem (Though I am not sure) is this:

Most of the time when the engine has sat for an hour or so maybe 2, I have to choke it to get it to start. My other 9.5, which is a 1972, considerably more hours and the bearings aren't too tight etc, can usually sit an hour or two and not need the choke to start.

Normal?