1988 Evinrude 25hp first run q's

joho5

Chief Petty Officer
Joined
Aug 14, 2008
Messages
456
Well i recently acquired this motor. Its a long shaft motor and my first run was on a regular size transom. It started up fine and pumped water fine. I then proceeded to set the slow speed setting and idle setting. I took off and it took off and ran pretty good...there was some drag due to the long shaft on a short transom. I stopped out in the middle of the lake and adjusted the trim a little bit, and wanted to see how it would start after killed. Started fine...idles good.

On my way back it ran rough, it would get to top end and sounded like it was just running rough or bogged down.

I was just wondering if the long shaft sticking down too far could have caused this. The initial run out there was only about 500 yards. (1 minute or so).

I brought it home and cleaned the carb. I found out that its missing 1 part on the carb...the little friction retainer that goes in right before the slow speed needle. It keeps the low speed setting and the needle from being loose.

From what I have stated, do you guys think the rough running could have been a dirty carb (it seemd really clean), possibly the missing friction retainer (does this take part in sealing air at all), or possibly the water pressure from the lower unit down too far in the water?

thanks...and I am in the process of making a 4-5" jack plate to get it to normal.
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: 1988 Evinrude 25hp first run q's

look the diagram of your carb here http://shop2.evinrude.com/ext/index.aspx?s1=bf6ad09c53cead335fcfd8a6471c0f7f
# 19 is the high speed jet, probably partially clogged. thats a special tool to remove it. then follow these direction, if you did not use a rebuild kit, you probably waste your time.
http://forums.iboats.com/showthread.php?t=244013

and here are Joe Reeves adjustments for the slow speed needle

(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: 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.

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.
 
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