Turned Idle Screw TOO FAR???

ptownmobber

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Apr 3, 2006
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Hello, got a 1988 Ev 15 horse. Just rebuilt carb and installed new kit. Replaced Carb top with new (seems less reinforced) top. Question here is when yall say turn screw "to seat" do you mean:<br /><br />- turn clockwise until tip inside hits case back OR<br /><br />- adjustment handle on outside that im using to turn screw hits gasket on outside of engine case?<br /><br />Im just scared that ill turn the damn thing too far and put a hole through the back of carb case top.<br /><br />All this is leading to try and get motor to idle properly. Trying to kill one problem at a time though. Thank you in advance for anyones help.
 

Xcusme

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Re: Turned Idle Screw TOO FAR???

Welcome to iboats!<br />Don't get scared...remove/insert the adjustment knob as needed and screw-in (clock-wise) the needle until it fully seats (lightly). Then 'open' the needle (counter-clockwise) 1 1/2 turn. Remove the knob and replace it so that the knob pointer is at 6 o'clock.<br />The carb is now setup for final adjustment. <br />BTW, you should have a fixed high-speed jet, no adjustment is necessary.<br /><br />(Carburetor Adjustment - Single S/S Adjustable Needle Valve)<br />(J. Reeves)<br /><br />Initial setting is: Slow speed = seat gently, then open 1-1/2 turns.<br /><br />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.<br /><br />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.<br /><br />Note: 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.<br /><br />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.<br /><br />(High Speed Adjustments)<br />At full throttle, with the proper size screwdriver, slowly start turning one of the H/S needles in segments of 1/8 turn, waiting momentarily for the engine to respond, then repeat turning. You will reach a point where the engine will start to die out. At that point, back that needle valve out approximately 1/4 turn. Now, go to the other High Speed needle valve and repeat that procedure. At some point in that 1/4 turn out, you will find the smoothest high speed setting (you can now lower the throttle rpm). That will have both high speed needle valves set correctly, and at that point you can lift that center lever adjustment of that high ridge, keeping it lifted until the point is facing the engine, then lower it into its proper position. (When you turn that lever now, you're adjusting both High Speed needle valves at the same time.)
 

ezeke

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Re: Turned Idle Screw TOO FAR???

When you "seat" the needle, just touch it, you will feel it stop. Too much pressure and you will cause it to stick. It is soft metal and easily scratched.<br /><br />There is a good on line manual for the 15HP: <br /><br />Click Here
 

ezeke

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Re: Turned Idle Screw TOO FAR???

Often the symptoms you describe for the shifting problem are caused by the shift rod being improperly adjusted. You will want to check that before disassembly of the gearcase. It is adjusted at the top.<br /><br />You may also want to make sure that noone removed the philips head screw from the lower end of the gearcase.
 

ptownmobber

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Re: Turned Idle Screw TOO FAR???

Xcuse and ezeke,<br /><br />Thanks for the help but the new top i put on the carb appeared to be a plastic material and not a soft metal. Thats why im worried bout turning the screw too much and putting a hole through the case top. Will i be able to feel it "seat" if im using the adjustment knob to turn it in? Will the outside motor case limit me from turning it too far?
 

ezeke

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Re: Turned Idle Screw TOO FAR???

I was speaking of the needle valve itself. The small seat that it goes to is also metal, and is within the top housing. If you will go to the BRP parts diagram and tell me the numbers on the drawing, we will get this right. See the link in the earlier response.<br /><br />When you turn the needle valve clockwise it should turn relatively smoothly and easily until it seats or closes. You will feel it stop. Just dont go beyond that easy stop or you can damage the needle.<br /><br />BTW, when Joe Reeves wrote the material that is quoted above, he was not speaking of this motor.<br />The service manual says 1 turn out for the 9.9 and 7/8 turn out for the 15HP. <br /><br />When I read this I assumed that everyone was speaking of the low speed needle valve and the rich/lean adjustment. Now I am not sure that you were speaking of that, but rather of adjusting the idle speed which is something else.
 

ptownmobber

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Re: Turned Idle Screw TOO FAR???

My man sorry for all the confusion. I appreciate you stickin with me on this....<br /><br />OK, on the diagram Evinrude 1988 15hp E15RCCS, the needle i speak of is #22 and the knob that fits over it from the exterior of the motor. The housing top i replaced is #25 and thats what im worried about putting a hole in from turning the needle too far in. I totally rebuilt the carb and want to get this needle adjustment right BEFORE i diagnose anything else. I know the idle speed is the large black screw on the end of the tiller handle, but i have not done anything with that as of yet. Do you also know approximatly where this should be set too?<br /><br />Again thanks for any help you can give me.....
 

ezeke

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Re: Turned Idle Screw TOO FAR???

Got tied up today. Let me get back on this in the morning.
 

ptownmobber

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Re: Turned Idle Screw TOO FAR???

ok i took off the carb top and got it adjusted the way you said to and reinstalled it. Thank you for your help on that......... I think it should work now (hopefully)<br /><br />Still need advice on setting the idle knob on tiller handle and also on what you said was the shift rod not being properly adjusted. I did disconnect the rod where the upper unit and lower unit meet when i installed new water pump, but thought i put it back together properly. Where would i adjust it up top like you previously said? Oh and phillips screw is still there in l/u. <br /><br />Again thanks for all the help. Couldnt have done this without yall
 

Xcusme

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Re: Turned Idle Screw TOO FAR???

The shift rod connector must be properly positioned and be bolted correctly.<br /><br />I posted a small picture of the connector in another post... Connector Topic<br /><br />As for the tiller handle adjustment, after the carb is properly adjusted, the motor's idle RPM's can be set with the tiller adjustment.
 

ezeke

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Re: Turned Idle Screw TOO FAR???

If you are certain that you ar connected properly below, then, At the top, you need to put the gearcase in reverse, then disconnect the shift lever linkage by removing the cotter pin behind the fuel hose. This should allow the gears to seat properly. <br /><br />If your motor is not set up exactly that way, there is still an adjustable link of some type. <br /><br />Then you can adjust the shift lever's connection to the shift rod, and reconnect.<br /><br />To shift while not running, you will want to turn the prop by hand with the spark plugs out.
 

ptownmobber

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Re: Turned Idle Screw TOO FAR???

Got it workin!!! Thanks for all the help you two. If yall ever need some Bar-B-Q tips let me know cause thats bout all i can help with haha!
 

ptownmobber

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Re: Turned Idle Screw TOO FAR???

Oh crap ps:<br /><br /> Whats a good setting to start my idle screw on the tiller handle before i begin adjustments?
 

ezeke

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Re: Turned Idle Screw TOO FAR???

You want to set the idle in gear, warm, and in the water. Best if you tie the boat to the dock while you do it. Unless you have a tach, take it down as slow as you can while keeping it running steady under the above conditions.
 

pontoon chief

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Aug 9, 2004
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Re: Turned Idle Screw TOO FAR???

Ezeke,<br />I read the link you provided for the Johnson/Evinrude online manual for the 9.9 and 15 hp motors.Great stuff.Are you aware of any similar sites for the small Merc's?
 

ezeke

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Re: Turned Idle Screw TOO FAR???

To Patrick B:<br /> <br />No, but I don't follow other makes anymore.<br /><br />Ask for that info on the Mercury Forum. There's got to be stuff out there.
 
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