1985 9.9 Johnson Sea Horse

[Gerard1]

Is recoil spring housing replaceable by itself? The slot in mine seems to have deformed and spring slipped inside housing and won't recoil.
Motor starts and idles ok but high speed runs then dies out. How important is tank pressure. Replaced old bulb and line and pumping the the bulb seemed to help at first but erratic performance returned until spring problem ended float trip. Just recently had to tear carb down to remove varnish and maybe some still in there floating around.
Also foolishly took apart fuel pump even though it was only 4 years old and I think I put it back together correctly. If I didn't would motor run at all.
Many more questions but first need to have a beer while I put away mouintain of gear my son and I had loaded for Susquehanna trip.
Can 9.9 main jet be replaced with 15 hp jet without any issues? Since I'm going to tear down carb anyway I might as well have more speed when I'm done.

 

[Joe Reeves]

Re: 1985 9.9 Johnson Sea Horse

Manual starter housing is part number 389204, available separately.

Fuel tank pressure is not required. Rather the tank must be vented... if air can't get in, fuel can't get out.

Clean the carburetor thoroughly BUT make no attempt to modify it.

 

[Rick.]

Re: 1985 9.9 Johnson Sea Horse

So many questions! I have had the recoil spring slip inside the housing before, actually several times on different motors. My fix is to cut a 1/4 inch copper tube the same or a smiidge longer than the width of the recoil spring. Wrap the end of the recoil spring around the copper pipe using heat if necessary to obtain a snug fit. Once you get a coil and a half around the tube, use a small tie wrap through the copper and around the coiled spring and cinch it as tight as you can get it. I haven't had one pull back into the housing using this method of fix. Yes you can order a new spring also but I'm too cheap to throw away a spring I think I can fix. Replacing the coil spring is a dirty job so wear old clothes. You should have an OMC service manual to rewind the spring correctly but my first time I got it done without one.

Won't run at high speed is probably because of your high speed jets not being clean enough. Could be fuel pump too but you never said if you pulled the pump apart before or after the high speed faltering occurred.

You don't have tank pressure, in fact the tank is under suction and therefore must be vented. Negative pressure in the tank could also be the cause of your high speed performance issue.

See link below for reassembly of the fuel pump. Take a good look at this link cause there is so much useful information for a 9.9 owner.

Main jet is not removable so forget about that idea. You could put a 15 HP carb. on it but I wouldn't. Best of luck and sorry if your trip was spoiled. Rick.
http://www.sschapterpsa.com/ramblings/OMC/OMC info.htm

Here is another link to see a parts break down for you recoil and the rest of your motor as well.
http://shop2.evinrude.com/ext/index.aspx?s1=5db2daa4014fa319c47f8ce315d5ee20

 

[DGartzos]

Re: 1985 9.9 Johnson Sea Horse

It is not a case of more gas alone to get higher power output of your motor. It is a case of bigger volume of balanced air/gas mixture it needs. The 15HP carb has a wider throat, a larger main orifice plug and a smaller idle orifice plug than the 9.9HP to feed motor properly.

 

[Gerard1]

Re: 1985 9.9 Johnson Sea Horse

Is recoil spring housing replaceable by itself? The slot in mine seems to have deformed and spring slipped inside housing and won't recoil.
Motor starts and idles ok but high speed runs then dies out. How important is tank pressure. Replaced old bulb and line and pumping the the bulb seemed to help at first but erratic performance returned until spring problem ended float trip. Just recently had to tear carb down to remove varnish and maybe some still in there floating around.
Also foolishly took apart fuel pump even though it was only 4 years old and I think I put it back together correctly. If I didn't would motor run at all.
Many more questions but first need to have a beer while I put away mouintain of gear my son and I had loaded for Susquehanna trip.
Can 9.9 main jet be replaced with 15 hp jet without any issues? Since I'm going to tear down carb anyway I might as well have more speed when I'm done.

Ok. So I did run the motor after I fiddled with the fuel pump and it ran perfectly at first, died out after about a mile then ran quite nicely for a day/night on the river. In fact it ran fast as ever. Just as we were preparing for this last float I was running the boat up and down the river but had to pump the fuel bulb every 15/20 seconds as the motor would begin to die. It would get back up to speed and then die out over and over again. Is it possible that the pumping is forcing gas past an obstacle in the carb, say a piece of grit in a jet?
Which jet is the one which is easily accessible and hangs down in the bowl? I suppose I could look at the site you mentioned as it is very detailed but I'm already typing so I might as well ask.
I'm Mr. Common Sense and I am realizing I need to remove the carb and clean it out again. I'll bet there is some residual varnish floating around. Will compressed air blow out the jets I can't remove?
I think I'll try the copper tube method on the recoil spring while I'm operating on the carb. Thanks.
Bob

 

[bktheking]

Re: 1985 9.9 Johnson Sea Horse

These fuel pumps are almost impossible to put back together correctly without the 18 step rebuild instructions that come with a new pump kit. I had one apart and it took me 4 tries with instructions to get it right.

 

[Rick.]

Re: 1985 9.9 Johnson Sea Horse

Ok. So I did run the motor after I fiddled with the fuel pump and it ran perfectly at first, died out after about a mile then ran quite nicely for a day/night on the river. In fact it ran fast as ever. Just as we were preparing for this last float I was running the boat up and down the river but had to pump the fuel bulb every 15/20 seconds as the motor would begin to die. It would get back up to speed and then die out over and over again. Is it possible that the pumping is forcing gas past an obstacle in the carb, say a piece of grit in a jet?
Which jet is the one which is easily accessible and hangs down in the bowl? I suppose I could look at the site you mentioned as it is very detailed but I'm already typing so I might as well ask.
I'm Mr. Common Sense and I am realizing I need to remove the carb and clean it out again. I'll bet there is some residual varnish floating around. Will compressed air blow out the jets I can't remove?
I think I'll try the copper tube method on the recoil spring while I'm operating on the carb. Thanks.
Bob

When pumping the fuel bulb gets it running right it indicates the fuel pump is not working up to snuff. Did you look at the fuel pump rebuild thread I sent and confirm yours is put together correctly? It is your high speed jet. You should always use compressed air to clean out the carb. holes after cleaning. It is strange that your fuel problem in intermittent. Normally it doesn't get better, just weaker and weaker. Your venting the tank properly?