Case of the Drips!

[Korbs67]

Hi Forum.
Before I tear into the just cleaned and put together carbs, has anyone seen this drip off the lower throttle screw before? If so, What ended up causing the leak. I reused the bowl gaskets as they appeared to be in great shape. I know thats not causing the drip at that spot..acutally maybe from the upper carb it is. I ordered a new bowl gasket from iboats just in case.

I checked the fuel hoses prior to re install they looked fine but if tear it down again I'll replace them just in case.

Any other idea please chime in.

Thank you so much.

Sorry if the picture is sideways..

 

[Korbs67]

Re: Case of the Drips!

Update on this issue. This an '89 Merc 60HP. B396723. Rebuilt, complete tear down.

The fuel puddling up in the front part of each Carb entrance there is a little port sticking up. This happens on both but the lower one a little more. The lower part of the throttle shaft still drips. When I pump the fuel line it hardens and fuel does not exit that little port in the front. It did this when I first pumped up before initial startup. Not sure if thats relevent btut I thought I'd mention it.

I wiped all fuel from carb area and ran the motor at idle for a few minutes. This gave me a good look at the gaskets and none of the gaskets are leaking.

When I had the carbs off before, I cleaned them thoroughly. The ONE thing I know I changed was the float height. My manual says 11/16" (17.5mm). 17.5mm is quite a bit more than 11/16". I chose to set them both at 17.5mm. Originally they were at more toward the 11/16" range so I did raise them up quite a bit. So I'm now wondering if the fuel bowl is holding too much fuel and its leaking out the front and somehow its leaking down the throttle shaft which is located more toward the rear. I can't get a good look at the entire throttle shaft but I noticed some wetness in the middle between the carbs that I can see.

I'd like to note that I rebuilt this motor and it runs great (I'm happy it started when I turned the key!). I'm running a rich fuel mixture of 25:1. There is a lot of exhaust at idle and its just seems to idle rough. Maybe it's missing, not sure.

C'mon all you veterans I need a tip on this. Are my floats up to high? Please for some feedback.

 

[Korbs67]

Re: Case of the Drips!

C'mon. 143 views. Please help the new guy here I checked lots of other carb drip threads and think it might be my float height.

I should also mention I disconnected the Autoblend..not sure if that has any significance.

The manual I have, the PDF download version, says float height should be 11/16" (17.5mm). I was incorrect in what I said about these not being equal. they are. I just wonder if I should be at 9/16th or at 1/2". Anybody know about these type C square bowl carbs?

Thanks!

 

[Chris1956]

Re: Case of the Drips!

That drip is likely from float height or inlet needle/ seat issues or some combo. It is likely the fuel is bubbling up into the venturi. Gaskets are not going to stop that. so:

Inspect the inlet needle, seat and float. Replace all if any look worn or leaky or cracked or heavy. Reset float height to spec.

 

[carholme]

Re: Case of the Drips!

What manual are you using as the one I have in front of me states 13/32" (10.3mm)

Gerry

 

[Korbs67]

Re: Case of the Drips!

I'm using a PDF manual i got online. It's pretty comprehensive but pictures are bad. I'm all for going with what an official current shop manual calls for.
To be clear. The is a square bowl carb type C. My serial number is 0B396723. A 1989 60HP

carlholme: I want to confirm how I measure is the float is correct.

--Turn the bowl upside down. With the needle in I measure from the bowl gasket surface(the mid point to the the highest(lowest when bowl upside down) part of the float. The float is not cracked, the pin appears to be perfect..sharp point, no wear, moves freely. The float respondes lightly when dropped on the height lever thing..its not heavy and isn't holding fuel. Fuel lines are not leaking fuel they are tie wrapped very snug. Fuel diaphram not leaking, new kit put on that too. Water pump peeing hard.

So if I go to 10mm the bowl will be holding more fuel before the float stops?? Right now I'm 17.5mm. Still getting fuel pooling at from of carb entrance.

Both upper and lower carb are set identical and pass the blow test. I have to really blow to get air through but I chalk that up to passages being so tiny. I blew carb cleaner and lightly compressed air through each hole repeatedly.

NOTE: I replaced the #1 piston(among other mechanicals, not electronics) because it detonated a couple years ago witha pop and powered down..I made back in on two pistons. There was an aluminum wafer over spark plug hole #1. Upon dissassembly i noticed #1 piston and Cyl 1 were bone dry, top carb that feeds #1 was bone dry and the fuel pump was bone dry with a hardened diaphram. Compression before rebuild was 60, 85, 85. After P1 replacement and new rings on 2(3 rings) and 3(3 rings) my compression is 130,137,139. I tested with elec start whereas it was a pull start before teardown.

Anyway, yesterday Piston 1 powered down- no pop, and I got home on two cylinders( it acutally ran great..very slow but great).
I immediately took plugs out and P1 had the same aluminum wafer covering the spark plug hole. I removed the wafer, peeked in as well as I could the crown of the piston looked okay, nothing is stuck and Compression readings didnt change.

From what I read on the forums I'm best served to have Cyl 1 timed at -2 from spec and run rich. I run 25:1, good new gas directly during break in, auto blend removed. I opened a thread on my stator, trigger and coil resistance test and was recommended to test with a DVA adapter. I dont have one and hate to buy one. Since I prob won't time it, unless it's easy. I'll probably just pay the 1 hour labor (quoted for link/synch, timing and carb adjust) and have them time this thing for me and make sure my electronic are up to snuff. My guess is I have original wires but before I plunk $80 into new wired I'd like to know if I stand a chance of this thing running like it used to.

I really need help in identifying the root cause of this repeated failure. Please, any guidance is appreciated.

 

[carholme]

Re: Case of the Drips!

Re the float setting:

Is it the Clymer manual you are using? My apologies for the 13/32" (10.3mm) setting, which is for the merCarb. If yours has the enrichment valve instead of the standard type choke, the following applies and you must note if you have the hollow or solid float:

Fig. Mii-7—To determine float level, invert carburetor
body and measure distance (D) from carburetor
body to base of float (15). Distance (D) should
be 11/16 inch (17.5 mm) on solid type float and 19/32
inch (15.1 mm) on hollow type float.

Gerry

 

[Korbs67]

Re: Case of the Drips!

Gerry,
My manual just says PDF Manual Publisher 2005. I have a choke solenoid hooked to the carbs so I beleive it is the enrichment valve type with a hollow float. Merc Part number#19273 which is definitely not a solid float.


Thanks for your time. Here is how i set the float height. By "carb body" is this what is meant? Did I measure correctly? It is currently set at 17.5mm from the highest part of the float. The front of float is 2mm lower than the back so I wonder which i measure from..probably the back part since it touches the fuel first but I thought I'd ask.

Also, What do you think of the condition of my inlet needles?(pictured)

Thanks!

 

[carholme]

Re: Case of the Drips!

Dug up a condensed version of the Clymer service manual. Let the page load for several seconds and then download to your computer soonest as the link is short lived.

http://web.ebscohost.com/serrc/pdf?sid=eaa33f4b-b445-4b68-8c45-6961c29118a3@sessionmgr14&vid=4&hid=7

See float setting picture at fig M11-7. You look like you have it right. As for the large needle, I don't know if it is just my tired old eyes but is the tip OK?

Don't know if you have the parts listing for your engine but here it is.

It is a model:

1060412GD MERCURY 1989 60

http://www.crowleymarine.com/mercury-outboard/336.cfm

Gerry

 

[nokiddin]

Re: Case of the Drips!

Hey Korbs, did you ever figure out what your problem was? My 84 90 HP merc seems to be doing the same thing with gas running down the throttle link from top carb all the way to the bottom of the bottom carb. Wondering if you figured out your problem.

 

[Korbs67]

Re: Case of the Drips!

Nokiddin,
I never pinpointed the cause. But I know there is a rubber gasket that is under each spring and washer for the throttle shaft. I still get minor drippage after adjusting the float height. I am replacing gaskets, needles&seats on both carbs this weekend. The throttle shaft through holes, as far as I can tell, have no place to leak. I suppose if gas sit in the carb it can leak through the throttle shaft holes but it should not affect performance. I'd say adjust the float height and make sure your needles and seats are replaced..bowl gaskets too while your at it. I bought my parts from this site for a total cost of 35-40. Two carbs.

 

[nokiddin]

Re: Case of the Drips!

Thanks for the help Korbs