Carb Rebuild

[BassBlaster29]

I'm rebuilding the carb on my QD-17. How tight should the packing nuts be. I assume it needs to be tight enough to compress the packing around the needle valves?

 

[AlTn]

Re: Carb Rebuild

exactly right..so you can still turn the needle valves w/o too much effort with the knobs attached

 

[BassBlaster29]

Re: Carb Rebuild

K, thanks, thats what I figured. How many of the packing pieces should I use. The rebuild kit came with enough to put 3 in each valve. The directions only show 1 being used but I read another post where it says to just put a couple new pieces in on top of the old ones cause the old ones are hard to get out. I got the old ones out. There were 2 pieces in each valve so I put 2 back. Should I add the third or is 2 enough?

Also, does anyone know where to get a new high speed needle. I have searched the net over and cant find one. The one in the card has just the slightest bit of wear on it. Almost not even noticable. Probably is nothing but I would like to locate one just in case I need it.

My plastic float finally came today so I can get this thing back together tonight!!

 

[HighTrim]

Re: Carb Rebuild

2 is all I ever put in. I am almost done a full restore on a QD16.

Dont over tighten the needle before backing it out. As stated, if you cannot turn the handles on the needles, the nuts are too tight. Just snug them up. If you havent already read it, check out the FAQ for a thread by Joe Reeves on fine tuning the needles on the water. Post a pic if you can of the needle, may still be fine. I might have a couple spares that are good around, Ill look for you.

Side note, is the fuel line original? Might want to change it out while you are at it.

 

[BassBlaster29]

Re: Carb Rebuild

I think I have read everything on the net about these old motors. I do plan to change out the fuel lines. The ones on the motor and the tank. Just havnt gotten that far yet. Thanks for the help!!

Heres a pic of the needle. I cant zoom in any closer or it gets blury. You can see the little bit of wear though.

 

[lindy46]

Re: Carb Rebuild

That's the low speed needle. What I do is put it in my electric drill (mounted horizontally in a vise) and spin it. Then I take a point file and grind her to smooth her out. Finish by using some 400 grit wet/dry paper.

 

[BassBlaster29]

Re: Carb Rebuild

Yeah, I figured out thats the low speed and not the high. I figured it could be resurfaced somehow. Theres definately enough material. I got it all back together and she's definately running better than before the rebuild. The low speed side tuned up great. The high speed side is another story.

With the cowl off it runs like a scalded dog. With the cowl on, I'm at a point where if I turn it in or out, it gets worse. It dosnt run bad where its at but it seems like there should be alot more rpm's. If I take the cowl off and turn the high speed needle out about 1/8 to a 1/4 turn it runs incredibly well. Also with the cowl off, the throttle response is incredible. I can snap the throttle and it takes right off. With the cowl on I have to ease into the throttle very easy to keep from killing it. What gives?

 

[jonesg]

Re: Carb Rebuild

Yeah, I figured out thats the low speed and not the high. I figured it could be resurfaced somehow. Theres definately enough material. I got it all back together and she's definately running better than before the rebuild. The low speed side tuned up great. The high speed side is another story.

With the cowl off it runs like a scalded dog. With the cowl on, I'm at a point where if I turn it in or out, it gets worse. It dosnt run bad where its at but it seems like there should be alot more rpm's. If I take the cowl off and turn the high speed needle out about 1/8 to a 1/4 turn it runs incredibly well. Also with the cowl off, the throttle response is incredible. I can snap the throttle and it takes right off. With the cowl on I have to ease into the throttle very easy to keep from killing it. What gives?

Exhuast leak choking it.!
if you can't track any leaks down visually you can add a bit of seafoam to the fuel, it will make the exhaust smoke like a train.

 

[HighTrim]

Re: Carb Rebuild

Likely the gasket, not a big deal to remedy

 

[BassBlaster29]

Re: Carb Rebuild

Okay, you guys have me confused now. Exhaust is choking what? What gaskets are we talking about here. I'm a rookie so you'll have to spell it out, lol. Thanks!!

 

[jonesg]

Re: Carb Rebuild

exhaust gas is choking the engine air intake, it needs air to run but its getting exh gas.

 

[HighTrim]

Re: Carb Rebuild

Check out the parts breakdown here

http://www.marineengine.com/parts/v...ntage-evinrude-johnson/376747/37674700001.htm

Part number 16, page 10, 303892 Gasket is a possibility, but try a decarb as stated and see if you can visually see where the leak is. As stated, exhaust gases are pooling inside of your cowl causing the conditions you describe.

 

[BassBlaster29]

Re: Carb Rebuild

I did the decarb. I got lots of black gunk out of the motor. I couldnt find a single place where any exhaust was coming out except for where it was suppose too.

I also replaced the plugs. I was still using the plugs that came with the motor because I knew I was gonna be doing the decarb and didnt want to burn up a new set.

Part of the problem too was I backed out the slow speed needle 1 1/2 turns per "top secret file" and that wasnt enough. Its currently about 1 3/4 turns out and the high speed is somewhere between a 1/2 and 3/4 turn out. I cant believe how sensitive those things are. She's running like a champ now though, even with the cowl on!! Will idle down to just barely running and the snappy throttle is back and runs smooth as can be on the high side. I still feel like there should be a few more rpm's but she's running good. Now I need to get the boat finished up so I can get her out on the lake and fine tune it!!

Thanks for all the help guys. This site has been a blessing!!

 

[cr2k]

Re: Carb Rebuild

One source of exhaust intrusion into the cowl is from a missing rubber seal around the shift shaft where it goes thru the bottom of the cowling. This can let gases from the exhaust housing into the cowling and displacing the o2 rich air with exhaust.

 

[BassBlaster29]

Re: Carb Rebuild

I dont think I have an exhaust problem at all. I think it was a combination of the old burnt plugs and the slow speed jet being turned in too far. Either way, she's running good now. Heres a video i made of it running after the decarb and the new plugs this afternoon.

 

[lindy46]

Re: Carb Rebuild

I did the decarb. I got lots of black gunk out of the motor. I couldnt find a single place where any exhaust was coming out except for where it was suppose too.

I also replaced the plugs. I was still using the plugs that came with the motor because I knew I was gonna be doing the decarb and didnt want to burn up a new set.

Part of the problem too was I backed out the slow speed needle 1 1/2 turns per "top secret file" and that wasnt enough. Its currently about 1 3/4 turns out and the high speed is somewhere between a 1/2 and 3/4 turn out. I cant believe how sensitive those things are. She's running like a champ now though, even with the cowl on!! Will idle down to just barely running and the snappy throttle is back and runs smooth as can be on the high side. I still feel like there should be a few more rpm's but she's running good. Now I need to get the boat finished up so I can get her out on the lake and fine tune it!!

Thanks for all the help guys. This site has been a blessing!!

So you've just been running the motor in a test tank? That would explain why it runs poorly with the cowl on. Exhaust gasses don't vent properly. Get her out on the lake and you shouldn't have any problems.

 

[lindy46]

Re: Carb Rebuild

And don't rev it up like that in a test tank - only in the water and in gear so cooling water properly enters the inlet on the fin for proper cooling.

 

[BassBlaster29]

Re: Carb Rebuild

Well, I thought the idea was to get it tuned up as close as possible and then go to the lake for fine tuning. Makes no sence to me to keep traveling back and forth to the lake untill I know this thing is gonna run. So, whats the purpose of a test tank if your not suppose to test your motors in them?

As far as reving the motor in the tank, you can cleary see the impellor was getting plenty of water and the motor was reved for less than 30 seconds. Not even long enough for the motor to get warm let alone get hot or over heated.

 

[HighTrim]

Re: Carb Rebuild

That cork float was still in good condition as well. I reseal them with 3 or 4 goods coats and they are good to go. Some are in terribble condition and need obvious replacement.

I am going to second not revving your motor like that in a little test tank. Im not going to type out a whole speech, but search thermal runaway and you will understand why.

Didnt know you were testing like that, had it been acting up on open water, an exhaust leak would have been your issue.

 

[BassBlaster29]

Re: Carb Rebuild

I thought the cork was in good shape too but I had allready ordered the new one prior to tearing the carb apart so I figured I'd go ahead and replace it. Now I wont ever have to worry about it. While were talking about the floats though, what do those get coated with? I kept it because it was in good shape. Never know, I may need it in another motor in the future.

I still dont understand why I cant run the motor reved up in the tank but you guys are more knowledgable than me so I wont run it in there anymore. It's close enough now that its ready for the lake anyhow. I do understand that the water can get hot so when I was running it earlier, I had the hose in the tank and the tank just overflowing so it always had fresh cold water going to it. The motor never got even remotely hot. I read that you should be able to hold your finger on the head for a 3 count. I could lay my hand anywhere on the motor for any duration of time so I wasnt worried about over heating and it was obvious by the water spraying out that the impellor always had plenty of water too it. Anyhow, thanks again for all the help. I'm glad to have this thing running good!!