1999 Johnson 25 carb help req.

[Bobbywolf]

Ok, so I was out last weekend and out of nowhere the outboard quit on me when I slowed down, getting close to shore. Pulling it over I have no joy. If I prime it, the motor will start every time, but then die a second later. I then figured out that if I prime it, and then gun the throttle, it will take off, and work great from about 1/2 throttle to full throttle.

After an involentary very fast trip home I pulled the carb apart expecting to find the idle circuit clogged.

What I found was a pristine carb with the center brass tube broken off down deep in the emulsion tube (I think thats what its called).


Question 1. Is this replaceable? I'm thinking no, because I do not see it on any parts breakdown.

Question 2. Is this even the right carb for my outboard? My model is J25REEB, yet the J25R carb does not look like this in the parts breakdowns. Mine appears to be a 25JR carb judging by the pictures.



If I need to buy a new carb, I want to make sure it is correct for my motor. (but I guess you could argue that this one was working fine until that tube broke. I still have no idea how that is even possible).

 

[Faztbullet]

Sorry but you need to find a carb replacement as that is not sold separately. These break from engine harmonics. These harmonics can come from engine being overpropped,damaged prop, bent prop shaft

 

[oldboat1]

Can you carefully screw out that nozzle from the carb top? I'm thinking a load of ATF or ATF/acetone to ease the way, then a big dog screwdriver to span the tube and fit both slots. If you can ease it counterclockwise, you might get it to budge, then screw out. Once out, you might be able to solder a repair. But the part is not available, so try it with fear and trembling.

 

[Bobbywolf]

Faztbullet - That seems crazy to me, but plausible, since this motor is new to me and I do not know its history. Prop on it looks newish, and at WOT the rpm is 5850 which I know is a bit high (should be 5500 max). I just assumed the previous owner had a heavier boat. I might look for a more coarse prop while I look for a carb lol.

oldboat1 - if the emulsion tube is removable, I may be able to solder the pickup tube, thanks for the idea. I guess I essentially have nothing to lose as it looks like I am in for a replacement carb anyways.

Does anyone with a similar 25 know if my carb looks correct for this outboard? Thanks again.

 

[oldboat1]

For what it's worth, I couldn't find a flat-top styled carb for you model (think I looked through most of the '99 25hp carbs -- could have been a late change, I suppose, but I didn't see it.) But I don't own that one. Maybe another lister does.

 

[Bobbywolf]

For what it's worth, I couldn't find a flat-top styled carb for you model (think I looked through most of the '99 25hp carbs -- could have been a late change, I suppose, but I didn't see it.) But I don't own that one. Maybe another lister does.

I bumped down 2 years to 97, and pn: 0439378 sure looks exactly like the carb I have, and it fits a 25. The 1999 25J carb is the same pn again. The bonus is that it is still available, for a decent price ($165 US). I do not know for SURE if it is the same, but I think I'm going to take the gamble.

 

[oldboat1]

seems like a good bet. Check me, but kit with float appears to be 0396701.

 

[Bobbywolf]

seems like a good bet. Check me, but kit with float appears to be 0396701.

Yup, every part in that kit looks the same as the carb I have. No going back now, I just ordered it!

 

[oldboat1]

Post results. Sounds like a success story!

 

[Bobbywolf]

Ok, a bit of an update. The carb is several weeks out, so it was time to attempt a temporary fix so I can still use the outboard while I wait for a new carb. The design of this carb lends itself to pressing out the idle pickup tube. You could not do this on the vast majority of carbs, just due to their design, but I can actually press from the back side of where the tube is fit to the body.

A 3/32" drill bit, flipped upside down in the drill press, makes a ghetto pin press, and is JUST under the size of the tube, so I could press it out.


Using a 1/16" drill bit shank to stop the tube collapsing, I was able to straighten the tube. 1/16" is an excellent fit, it JUST fits inside the tube.




Now for the fun part. I cleaned up both ends with scotchbrite, used the drillbit shank as a splint, and soldered it back together.


Success! or so I thought. You may have guessed it, but yup, that drill bit crutch was now soldered inside the tube, and no amount of persuasion could remove it. Keep in mind the sizes I am dealing wither here are tiny.

I heated the whole mess up again with my torch, separated everything and cleaned it up. This time, I put a light coat of spray paint on the drill bit to try and combat the solder from sticking to it. This time it worked! I carefully extracted the bit, and used a Dremel and a bit more scotchbrite to clean up the repair.

I think 5 is my max pics per post, so continued below.

 

[Bobbywolf]

Now it was back to my makeshift pin press to overdrive it through the carb body so I could then add some sleeve retainer to try and make this tube stay put.




I added the retainer goo, drove it back flush, and then quickly cleaned off the excess, and blew shop air through the tube to ensure it was clear. The result is that it appears fixed, I can see straight through it, and I am sure it will work!




The only REAL question is; will it last? I guess only time will tell. It needs to last until my new carb arrives at least. I'll update again when I get the motor going again and the boat back into the water.

I'm showing all my steps here in hopes that it helps someone else in my position. Not a lot of info on fixing these pickup tubes.

Here's hoping for the best!

 

[oldboat1]

Really interesting!

(Don't forget the gasket down at the bottom.)

 

[James R]

Congratulations on a fine job. Good information and pics.
Two days ago I had to repair the outer tubes on two carbs from a 40Hp John.
They had split along the line of the 4 holes, both sides. As you are aware the small center tube is angled and is in contact with the inside of the larger tube and protrudes past the end of the larger tube. This is intentional. I am trying to figure out how this damage could occur. I note that without the gaskets the center tube appears to make contact with the bottom of the bore in the float bowl. So if the gaskets used were not thick enough or compressed too much this would cause the smaller tube to flex and load the larger tube perhaps causing sufficient stress to cause the damage.
Of course this is only my theory. Maybe someone has a better one.
The motor is back together and running sweetly. Only time will tell if our repairs hold up.

 

[Bobbywolf]

Well the verdict is in. It worked an entire weekend camp/fishing trip. About 2 tanks of fuel through it and still going strong. Which is good because my replacement carb still isn't here yet. I still honestly do not trust it enough to go out somewhere remote, with mine being the only boat. But it works for now.

I really wish I could buy just the pickup tube. On this carb in particular, it isn't very difficult to change. SOMEONE made it, so it could be installed into the carb when it was built. Seems silly to not make it available to the consumer.

 

[racerone]

Most folks simply have no idea how much it costs to maintain a parts warehouse that would cover 40 years of motors with 20 or more models each year and some with 600 parts each.-----Many products hit the market each year.-----No service or spare parts at all.----Just the way it has gone !

 

[Crosbyman]

have you googled "small brass tubing" ?? surely somebody makes it
hobby shops may have something for small airplanes or crafts