Reassembly of Leaf Block Assembly...

[Sportwinjoel]

Hi all,

I have started a carberator rebuild on my 1968 9.5 Evinrude. I am at the reassembly stage of the Leaf Block Assembly. Before disassembly all the leafs sealed correctly. I would hold them up to the light and see none creeping through. Upon putting the leafs and leaf stops on, with care to center according to the OMC manual I now have lost the seal. I have matched them to their original positions.

Do I need to purchase new ones? Is there a trick I am missing? It seems straight forward. The light comes through ever so small but I have lost the original fit.

Any insight would be appreciated.

Thanks

 

[Joe Reeves]

Re: Reassembly of Leaf Block Assembly...

Turn the leaf over.

 

[Sportwinjoel]

Re: Reassembly of Leaf Block Assembly...

Thank you sir I did try that. I am thinking the tightening of the 2 screws is lifting them. I have a torque value so I am going to use that instead of just tightening by feel.

Thanks for responding

 

[Daviet]

Re: Reassembly of Leaf Block Assembly...

Remember that when the engine is running there is pressure against the back side of the reeds, the pressure will help them seal.

 

[Sportwinjoel]

Re: Reassembly of Leaf Block Assembly...

I was wondering about that....because I feel comfortable that I have them centered. And I also feel that they are in great shape. Not bent or deformed in any way. As you all probably know the parts are a little pricey (not complaining)on these older motors and I don't want to reassemble after coming this far and miss something.

The original symptom of this motor was it would run for about 2-3 minutes pretty decent then cut out. When I advanced the choke it stay running a little more then quit. Did sputter a little as well.

I did find that the Low speed needle valve was real deformed on the tip. It looked bent and scored around it ...like some one has bottomed it out badly. So I have a new one on the way...$90.00.

Anyway thanks alot. I am going to move forward with the leaf (reed) block reassembly and now feel good about it!
Thanks Cadet LOL
Joel

 

[Rick.]

Re: Reassembly of Leaf Block Assembly...

Always glad to see someone learning however just thought I should mention your going a little beyond what most would consider a carb. rebuild. Normally reeds just keep on working forever without any maintenance. Not always but most of the time. Best of luck. Rick.

 

[Sportwinjoel]

Re: Reassembly of Leaf Block Assembly...

I appreciate your observation I to realized that I have gone beyond my original intention. LOL I purchased an original OMC manual and as I was following along it became apparent that I was deep into it. LOL It has been fun and I have learned alot. I do some wrenching in my job so it hasn't been real intimidating. I originally got into this project because of when I was a young man 16 I owned a 9.5 Evinrude. Once I purchased this one I have been really caught up in tinkering with it until I get it to run like I know it can. I want to say thanks again to all you all for your insight and help.

Cadet
Joel

 

[Joe Reeves]

Re: Reassembly of Leaf Block Assembly...

Your statement of "When I advanced the choke it stay running a little more then quit. Did sputter a little as well."

That indicates that either a air/fuel leak exists between the fuel pump and the fuel supply OR a faulty fuel pump.

 

[Sportwinjoel]

Re: Reassembly of Leaf Block Assembly...

Thank you admiral I put a new fuel pump on it can't wait to finish the job to see if I have it licked. I am waiting for the Low speed needle valve to arrive.

Thanks,
Cadet Joel

 

[Sportwinjoel]

Re: Reassembly of Leaf Block Assembly...

Well here we go I have been informed that BPR doesn't have a low speed needle available anymore....so if I could ask you all to help me locate one I would be much obliged. I would prefer brand new but in excellent shape used would do. Anything in better shape than what I have. Thanks for any leads.
Cadet,
Joel

 

[Daviet]

Re: Reassembly of Leaf Block Assembly...

Start calling
http://forums.iboats.com/showthread.php?t=438822

 

[Sportwinjoel]

Re: Reassembly of Leaf Block Assembly...

Thank you Commander. Very much appreciated.
Joel

 

[Sportwinjoel]

Re: Reassembly of Leaf Block Assembly...

Daviet or anyone else.....can someone give me there input on wether or not the replacement of the needle valve (part that the lean/rich knob attaches to) is a real deal breaker in the long run? It definitely is a little bent on the tip. Does anyone think I could successfully dress it up maybe? Appreciate it.

Cadet Joel

 

[Daviet]

Re: Reassembly of Leaf Block Assembly...

The angle is the important part, if you can dress it up and keep the angle real close you will be ok, be careful not to take to much off. On a solid needle, one with no flexshaft, you can chuck it up in a drill and dress it up with a fine file.

 

[Sportwinjoel]

Re: Reassembly of Leaf Block Assembly...

Thanks Daviet I loved the drill trick I will put that one in the memory bank. I was wondering maybe you know. On this particular motor (1968 9.5 Evinrude)
where does the end of this needle go? Does it sit in a seat? And if so does that have the possibility of being damaged? I don't get how this works. I got new brass parts in the rebuild kit and I didn't want this old needle valve which has some damage to hurt the new parts if they work in con junction with one another. The dressing of the old one can be done because it is brass as well. I will need to get it under a magnifing glass because I am over 40...I am fifty lol and the ole peepers aint what they use to be. Anyway I appreciate your help and insight.
Cadet Joel

 

[Daviet]

Re: Reassembly of Leaf Block Assembly...

I don't see a replacable seat in the parts breakdown, but you take a look and see what you can find.http://www.ishopmarine.com/ishop/jsp/AsplIsmCcatViewBase.jsp?&lvlCode=5&pCode=C0078703&path=BRP~A0000003~M0005059~M0005117~M0005118~C0078703&isFromCMS=false&hideAdd2CartButton=&isStandAlone=&is4CmsShop=&reqln=Unknown&reqem=Unknown&reqph=Unknown&reqFor=29&req4Browse=1&docId=&docName=&isForSupStore=false&cCatFilter=&eCatSupFldr=

 

[Sportwinjoel]

Re: Reassembly of Leaf Block Assembly...

Yea I didn't either but as I looked further into the Service manual I purchased It gives a short section on Carb theory and describes it like this:

"The carb is a metering device for mixing fuel and air. At idle speed, an engine requires a mixture of about 8 parts air to 1 part fuel. High speed mixture is about 12:1."

"A small chamber holds the fuel. A float valve admits fuel from the fuel tank to replace fuel as it is consumed by the engine. Meterjng jets in the carb throat extend down into the fuel chamber."

The upstroke of the piston in the cylinder creates a suction that draws air through the throat. A restriction in the throat, called a venturi, has the effect of reducing air pressure at this point, by controlling air velocity."

"The differential in throat and chamber air pressures causes the fuel to be pushed out of the metering jets and into the air stream. Here it mixes the air to form a combustible mixture for exploding in the engine cylinders."

Now here is the good part !

"In order to mix the fuel and air in just the right proportions for all engine speeds, the low speed jet has an adjustable NEEDLE VALVE to compensate for changing amospheric conditions. The high speed jet may have a fixed high speed orfice or an adjustable needle valve."

"To regulate engine speeds, a throttle valve controls the volume of fuel to air mixture drawn into the engine. To compensate for the extra amount of fuel required to start a cold engine, a choke valve is placed ahead of the metering jets and venturi."

"When the valve is closed, a very rich fuel mixture is drawn into the engine. As the engine starts and warms up, the choke is opened to restore the normal ratio required"

So I wrote all that to say this...I feel pretty confident a low speed needle valve tip in good shape is pretty important lol!

Once again thanks for helping me Daviet it is much appreciated. I hope a lowly Cadet like me can return the favor some time! I live in Florida and if I can ever check on anything for you here I would be glad to.

Joel

 

[Daviet]

Re: Reassembly of Leaf Block Assembly...

What part of florida are you in, you didn't list it.
I am orginally from south west part of the state.

 

[Sportwinjoel]

Re: Reassembly of Leaf Block Assembly...

I live in the Clearwater area sir. But grew up in Venice. How bout you?

 

[Joe Reeves]

Re: Reassembly of Leaf Block Assembly...

The slow speed needle valve does not have a replaceable seat. It simply seats upon a specific hole within the carburetor. On a worn needle valve, I always went the drill press or an electric drill secured in a vice route, then returned the bevel to a true condition with a file...... yes, that is important as a worn needle valve makes it impossible to obtain a low rpm setting. The following may be of some help to you.

(Carburetor Float Setting)
(J. Reeves)

With the carburetor body held upside down, the float being viewed from the side, adjust the float so that the free end of the float (the end opposite the hinge pin) is ever so slightly higher (just ever so slightly off level) than the other end. And when viewed from the end, make sure it is not cocked.

(Carburetor Adjustment - Single S/S Adjustable Needle Valve)
(J. Reeves)

Initial setting is: Slow speed = seat gently, then open 1-1/2 turns.

Start engine and set the rpms to where it just stays running. In segments of 1/8 turns, start to turn the S/S needle valve in. Wait a few seconds for the engine to respond. As you turn the valve in, the rpms will increase. Lower the rpms again to where the engine will just stay running.

Eventually you'll hit the point where the engine wants to die out or it will spit back (sounds like a mild backfire). At that point, back out the valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest slow speed setting.

Note 1: As a final double check setting of the slow speed valve(s), if the engine has more than one carburetor, do not attempt to gradually adjust all of the valves/carburetors at the same time. Do one at a time until you hit the above response (die out or spit back), then go on to the next valve/carburetor. It may be necessary to back out "all" of the slow speed adjustable needle valves 1/8 turn before doing this final adjustment due to the fact that one of the valves might be initially set ever so slightly lean.

Note 2: If the engine should be a three (3) cylinder engine with three (3) carburetors, start the adjustment sequence with the center carburetor.

When you have finished the above adjustment, you will have no reason to move them again unless the carburetor fouls/gums up from sitting, in which case you would be required to remove, clean, and rebuild the carburetor anyway.