Only WOT after carb rebuild - FIXED!!!

[Beefer]

1959 Johnson 10hp QD-20

I clean/rebuilt the carb last night, and now it won't run at any throttle setting except WOT. I started with the hi speed needle set about 2 turns out from lightly seated, but it ran tons better at <1/4 turn out from seated. I don't think that's good. Low speed I can't even come close to setting, because if I move the throttle off full, she cuts out pretty quick (less then 5 secs). I did notice that it seems the pitch changes in high when I'm turning the low speed needle in full. Is this an indication of worn out needle valves?

Over the weekend, I had her out and was running great at anything other then idle (which is why I decided to clean/rebuild). On Wednesday, I added a full can of SeaFoam to about 4 gals of fresh (<1 month old gas). On Wednesday after the SeaFoam, she topped out at about 6-8mph, and wouldn't getup on plane. I just added 4 gals more gas before starting it for the first time today, and had about 1.5 gals of the SeaFoam mix still in it. Is the SeaFoam my issue (which would be a non-issue), or is it something else?

One other thing, I can not get the low speed needle valve to stay in one place no matter how much I tighten the retaining nut, unless it's seated.

As always, thank you in advance.

 

[nwcove]

Re: Only WOT after carb rebuild

Re: Only WOT after carb rebuild

did you replace all the packing for the ls needle? the packing nut should really keep the needle in place if the packing is done correctly.

 

[oldybutagoody]

Re: Only WOT after carb rebuild

Re: Only WOT after carb rebuild

You're last comment sounds like the key. You're probably sucking air thru the low speed needle valve stem. Did you put two packing washers in when you rebuilt it? I most definitely should not be loose. It will never idle if it is. It could be other things like coils, points, head gasket. Etc. but I'd start with that low speed needle valve.

 

[HighTrim]

Re: Only WOT after carb rebuild

Re: Only WOT after carb rebuild

How many packing washers did you use for the low speed? Your carb has a removable bushing in the low speed, which can sometimes be a pain. You are likely not seated properly before you backed it out, leaving it too rich. Be sure you have adequate packing, then tighten the packing nut so that the bushing does not spin, yet still allows you to seat the needle. Then back it out 1.5 turns. The high speed needle needs to be backed out 3/4 turn to start. Turn the needles clockwise in small increments, giving the motor time to respond, until it wants to die or starts backfiring, then back it out 1/4 turn. Within that 1/4 turn is the ideal position.

What was the condition of the fuel lines? If they are original they must be replaced.

The Seafoam may have looseded some crud in the fuel system. Try some fresh fuel and let us know what you find.

EDIT: Boy am I slow at typing, lol

 

[Beefer]

Re: Only WOT after carb rebuild

Re: Only WOT after carb rebuild

In all honesty, I did what I thought was right, but ended up with a bunch of extra gaskets, o-rings, and synthetic washers for the carb kit. During disassembly, the needles each had one 'clear' washer, then a rubber gasket. During re-assembly, the o-rings wouldn't fit (too big), and I put in 2 synthetic washers (they were the only things in the kit that fit). I still have 4 synthetic washers, and the 2 rubber o-rings just sitting in the bag. The extra gaskets look like extra mounting gaskets for various carbs. I replaced the one mounting gasket that was there with a matching one from the kit.

 

[Beefer]

Re: Only WOT after carb rebuild

Re: Only WOT after carb rebuild

The fuel lines and pump are all new, filter is spotless.

Should I add more of the packing washers? Maybe one in each, and see how that goes?

 

[HighTrim]

Re: Only WOT after carb rebuild

Re: Only WOT after carb rebuild

Your high speed circuit uses 3 packing washers. Check out your parts diagram here

http://www.marineengine.com/parts/v...ntage-evinrude-johnson/377806/37780600001.htm

 

[Beefer]

Re: Only WOT after carb rebuild

Re: Only WOT after carb rebuild

Oy... And I was using that as a reference last night. But that's the high speed that they show with 3, isn't the low speed my big problem?

 

[Beefer]

Re: Only WOT after carb rebuild

Re: Only WOT after carb rebuild

Added a packing washer to the high speed, no change. Pulled the motor off, and I'm going to look at some other things (points. coils, etc.). How do you check timing on these things?

 

[nwcove]

Re: Only WOT after carb rebuild

Re: Only WOT after carb rebuild

make sure the carb is "right" before you move on to other things, or you will be chasing your tail !!! jmo

 

[Beefer]

Re: Only WOT after carb rebuild

Re: Only WOT after carb rebuild

Yeah, I'm going to stick with fiddling with the carb. I can't get the flywheel off for the life of me.

I wanted to check the coils. I've heard that they can deteriorate, so I was gonna take a peek. Oh well.

I'm really wondering if this could all be the high ratio fo seafoam in the gas. Does anybody know if this could be the cause? It ran great before the seafoam add, which was before the rebuild, but after a no-idle (but slow speeds were ok) issue.

 

[HighTrim]

Re: Only WOT after carb rebuild

Re: Only WOT after carb rebuild

Open up the inspection port in the flywheel and have a looksee

 

[Silvertip]

Re: Only WOT after carb rebuild

Re: Only WOT after carb rebuild

Let's see! You added seafoam in high concentration to clean the internals of the carb and now you have a carb problem. Come on! Yes it loosened up crud and plugged things up. You now have disassembled the carb, didn't pay attention to the needle valve positions (counted turns before removal), probably assembled the carb incorrectly and now the engine doesn't run right but you suspecdt points or timing. Timing doesn't go out of adjustment because you added something to the fuel. Leave it alone until you get the carb correct. Air leaks cause idle issues, clogged/varnished passages cause idle and running issues, improper float level and sticky needle and seat can cause running issues.

 

[Beefer]

Re: Only WOT after carb rebuild

Re: Only WOT after carb rebuild

I just got scolded by silvertip! I feel honored!

You're right, I didn't count how many turns when I was taking the needles out because a) the low speed needle was so loose that when it was running it would just spin itself out, so there was no real starting point, and b) nothing I read said to count on the dis-assembly (only the assembly; 1.5 & 2 turns off lightly seated).

The interesting thing was that there wasn't any noticeable clogs in any of the tiny jets. Yes, the carb was dirty, but nothing obvious, and no varnish on anything. It actually looked pretty good. It had the newer float valve assembly (rubber tip with spring) and the float itself is in fine condition.

As for the points/timing, it's not that I suspected them of being my problem, but more of 'might as well check these while I'm here' type of thing. I was more interested in checking the condition of the coils.

In the mean time, I broke the carb down again, cleaned everything again, and checked and double checked my re-assembly. I won't be able to test until tomorrow. So since I didn't count the turns on the needles, what is your suggested starting point? The rebuild kit says 1 turn off lightly seated for low speed, and 2 turns for high speed. Other guides (including a Johnson manual) say 1.5 low, 2 high.

I also put a bit of silicone over the expansion plug to insure that it doesn't leak.

One thing I noticed is that the new float valve and old float valves are different lengths. The new one is 0.535", and the old one is 0.70". Which one should I use? I have the new one in there, but I'm wondering if I should put the old one (which looks in fine condition) back in???

 

[HighTrim]

Re: Only WOT after carb rebuild

Re: Only WOT after carb rebuild

I mentioned in post#4 about setting the needles.

 

[lindy46]

Re: Only WOT after carb rebuild

Re: Only WOT after carb rebuild

2 turns out for the high speed is too much. Start at 3/4 to 1 turn out. Are you sure you have the right rebuild kit? Did you remove the welch plug on top of the carb and clean the idle circuit?

 

[Beefer]

Re: Only WOT after carb rebuild

Re: Only WOT after carb rebuild

WooHoo!!!

I posted this issue on a tin boat forum, and one guy suggested I check to see if some gunk got lodged in the spark plug gap. Sure enough, the top plug had a chunk in it. Cleaned it off (they are new plugs), checked the other, and did a test run.

I think I'm going faster now, and I can actually idle! WOOHOOOO!!!!

Anyway, just wanted to say thanks to everyone for their help, and maybe this will help some one else down the road.