Nissan carb teardown questions.

[oregonducker]

2002 NS40D2<br />Pretty easy so far. Everything is off but what about the two brass pieces in the picture? No screwdriver slots and they don't just fall out. Are they supposed to come out or not? I got a manual but it has absolutely nothing to say about taking the carbs apart. Kind of disappointed with that. Any specific pointers on doing the rest of the teardown/cleaning? How about float adjustment? The manual says where it's supposed to be but not how to adjust it and I don't see a way to do it. This is the upper carb, I'm doing them one at a time. Thanks, Dave.<br />

 

[rayjay]

Re: Nissan carb teardown questions.

The orifice on the Rt is the float needle seat. Non-replaceable. With a rubber tipped needle the seat basically last forever.<br /><br />The center bit is the emulsion tube { also called the standpipe and several other names } . May or may not be removable. If it won't come out with a moderate amount of pressure then just leave it alone.<br /><br />Looks pretty clean. Were there any deposits in the bottom of the float bowl ?

 

[oregonducker]

Re: Nissan carb teardown questions.

Just a tiny bit in that one. Haven't taken the other two off yet. Which is the high speed jet? Is it the one that goes in the hole to the left of center in that picture?

 

[oregonducker]

Re: Nissan carb teardown questions.

Ok I got the emulsion tube to pop out. It has various holes around the sides of it. Other than top and bottom does it have to line up a certain way when I put it back in?

 

[oregonducker]

Re: Nissan carb teardown questions.

On the center carb, the fuel inlet on the side is a plastic T over what looks like a brass fitting going into the carb. Does that whole unit unscrew from the carb or does the plastic T pop off the the brass piece. I don't want to twist or pull on it any harder than I have. Afraid I'll break it.

 

[oregonducker]

Re: Nissan carb teardown questions.

Well I got impatient and now it's broken. The brass part broke inside the T. See the pic. Now what? Can I get that brass piece out of the carb or am I now in the market for a new carb?<br />

 

[rayjay]

Re: Nissan carb teardown questions.

Sorry, I was out in the misty weather cleans my Evinrude carbs. Before I saw your last post I was going to say leave the nylon attached to the carb. Too late. You may end up having to buy another carb as I am about sure that piece isn't supplied separately. You could run a tap down the piece left in the carb body and heat the carb body with a heat gun { after washing all the gas off } and possibly pull the broken piece out. Then you have try and find a new nipple that is a perfect fit in the body. You might could tap the carb body and use a screw in nipple. You would end up using a fuel line tee and a short piece of hose to connect to the replacement nipple. <br /><br />The high speed jet is the lowest one in the carb. Probably down in the float bowl. The low speed jet is the one that was down the well on the left of the first pic. The emulsion tube just has top and bottom. <br /><br />Infernal combustion engines can sense impatience and rain sorrow down on your head when they can.

 

[Silvertip]

Re: Nissan carb teardown questions.

You don't have to buy a new carb. Tap the brass fitting for a hose threaded brass hose barb the size of your fuel line. Then buy a plastic "T" also the same size as your fuel line. Insert the hose barb (seal the threads) and attach a short piece of fuel line to it. Insert one side of the "T" fitting into the hose and clamp it. You now have the same thing you started with. Everything is available at your local auto store. The small tap to tap the carb is available at most home improvement centers.

 

[oregonducker]

Re: Nissan carb teardown questions.

Thanks for the info everybody. Wish I'd been a little more patient but I was hoping to get this done with enough time left in the day to go test it. Still don't have the lower carb off and apart yet but these first two sure look clean. Hopefully cleaning them anyway will fix it's high speed sputtering problem. Good learning experience anyway.<br />I will take the parts down to the store and see what I can get to fix it. Tapping it had sort of crossed my mind but now I'm definately going to check that out. JB weld was an idea too. Looks like it would be a pretty good situation for that but then I'd never trust it. I seem to have mixed results with JB weld. Tapping it is a much better idea.<br />What would you use to seal the threads?<br />Thanks again, Dave.

 

[Johnshan1]

Re: Nissan carb teardown questions.

I have a 2002 Tohatsu 40 hp and was wondering why you tore into the carbs in the first place? I always fog my motors and drain the carbs at the end of the season, by doing so I hope to avoid having to tear into the carbs for a few years yet. Just curious if you were having a running issue or just wanted to clean for good measure? Thanks,<br />-John

 

[oregonducker]

Re: Nissan carb teardown questions.

Running problems. Sputtering and such at higher speeds. It was suggested that look for air getting into the fuel and clean the carbs. I run this one every week of the year. It never gets put away so a carb problem sounded likely. They all look very clean but maybe there is something stuck in there somewhere.

 

[rayjay]

Re: Nissan carb teardown questions.

What did the plugs look like ?

 

[oregonducker]

Re: Nissan carb teardown questions.

Good. They're only a year old. <br />I did find something odd when I took the lower and last carb apart. The pilot screw (that's what the manual calls it I think it's the idle mixture screw) was just over 2 1/2 turns out while the upper and middle ones were at exactly 1 turn out. So I checked the manual. It says 2 1/2 is the starting point for all of them. I had this motor serviced a year ago in February in Portland, Oregon. Now I'm in Boise, Idaho. Almost 3000 feet higher in elevation. Would the combination of the higher elevation and the goofy screw settings cause problems?

 

[Silvertip]

Re: Nissan carb teardown questions.

Regardless of the altitude, both screws should have been set relatively close to each other. Use teflon tape to seal the taped threads. There are other sealers suitable for gas, oil, etc that work equally well. Just make sure whatever you use, bits of it do not find their way into the carb. Start the sealer one thread up.

 

[oregonducker]

Re: Nissan carb teardown questions.

When I get broken part fixed I'll start the settings where the manual says to.

 

[rayjay]

Re: Nissan carb teardown questions.

There are some Tohatsu carbs on Ebay. <br /><br />If this is the first time you have run the motor at the higher elevation then you may have to lean out the jetting to compensate for the altitude. The manual may have recomendations. <br /><br />I was hoping the plugs would look dark or for one of them to look substantially different from the others to give some clues.

 

[TOHATSU GURU]

Re: Nissan carb teardown questions.

Are you over 5000 feet?

 

[oregonducker]

Re: Nissan carb teardown questions.

No about 2800. Went from pretty much sea level to that.

 

[TOHATSU GURU]

Re: Nissan carb teardown questions.

Is your compression even on both cylinders?

 

[oregonducker]

Re: Nissan carb teardown questions.

Don't know and I don't currently have a way to check but I will if the carb cleaning etc. doesn't help. It's a 3 cyl.