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1988 Evinrude Xp Runs Away

Bamaboater

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Hi everyone! I am hoping someone can help me with my problem. And I defiantly appreciate all the help I can get. I just got a boat from a friend of mine and he was having issues with the mtr not wanting to start. Doing some checking I see it was having any spark. I figured that problem out it happened to be a faulty kill switch. I put fuel in the boat, primed it up and got it to start and here comes my problem. It dosnt idle, after firing up it goes wide open. I looked at the linkage throttle and choke and seen no issues. any idea why it would just take off and run wide open? what all do I need to look at? It has VRO but is plugged off and not used as he didnt trust it out on the water so now its a 50:1 mix. The motor is a 1988 Evinrude 150 XP Model # E150STLCCA I do have a Selco manual and another brand manual on the way. I just dont know what the culprit might be and I definitely dont want to run it long so I dont blow her up lmao. I appreciate everyone's help.
 
Broken reeds would slow the motor down.----Perhaps check the flywheel key ( controls timing )----Is throttle arm against the stop at idle ?
 
I agree with both Chris and Racer. Reed valves are pretty bullet proof on these besides. A substantial vacuum leak could also be the cause, or contribute to the cause. Compression test is always good to have as well. Maybe the linkage is disconnected to the trigger too, kinda what Racer is chasing.
 
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You say that you've looked at the linkage of the throttle and choke <--- That really doesn't do it.

The 1988 V6 Models DO NOT have choke butterflies... they have a Fuel Primer Solenoid. Make sure that the RED lever of the solenoid is pointed all the way at the other end of the solenoid which is the automatic running position. Any other position allows fuel to bypass the carburetors.

Remove the carburetor face plate and actually check that the throttle butterflies are "all" set to the closed position.

Check that the Timer-Base under the flywheel is not stuck and hung up at the full spark advance position.

Let us know what you find.
 
Tha is for everyone's reply. I think I've found the culprit. I am mechanically inclined but this is my first boat. The linkage wasn't all the way back. My terminology may not be correct soni will post a picture as soon as I get home. I've been looking through the book trying to figure out how to adjust it as the linkage pushes itself back out a little even when not hitting the stop. I can push it by hand and then it will idle. It's part of the linkage I assume dealing with the idle stop that is right under the flywheel.
 
But here in about an hour I will take a few good pictures and show you what I'm talking about. I do appreciate everyone's reply and I would assume that maybe some of its out of adjustment because all of the cables well actually everything on the entire boat is brand new. All the way down to the wiring the fuel tank brand new batteries brand new flooring and carpet the boat has been completely out re outfitted. I got it from an older gentleman who ended up breaking his leg and really isn't able to go out and fish anymore and had the boat completely redone.
 
what I am pointing at in the picture is what is opening up and causing it to throttle up higher. I can push it over, close it off and it will idle down but as soon as i let lo it open up slowly. It's never even hitting the stop.
 
BB, gotta shrink image to about 1000K. I use lit photo, anything will work. Sounds like a beautiful boat. Be sure to get us a picture. Thanks, Tim
 
Here is a link to you tube
of it running. You can see me pushing against it idling it back down, it'll actually rev higher if I let it go on longer.. When pushing it back it isn't hitting the stop. what could be the reason for this?
 
Excellent looking motor, something isn't right here, however. Is your control positioned in idle? Maybe you just have to adjust the cable. Help from another tech. Nice photo.
 
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My control is in the Neutral/Lock idle position. I was thinking cable but I don't see anything pulling on that rod itself. I am going to investigate it further in the morning. when it idles that high it kinda slams into gear, one of the issues I am trying to eliminate as well. Thanks to all the comments and help thus far.
 
From what I understand, and correct me if I'm wrong... what you're pointing at is the linkage between the timer base and the vertical throttle arm... and you're stating that the timer base moves towards the rubber capped Spark Advance Stop screw while the engine's running (Automatically advancing the spark).

Even if a friction problem existed between the flywheel and the timer base, that type problem would not cause the problem as when the the engine runs... the flywheel rotates in a clockwise motion... the timer base advances, moves in a counter clockwise motion (a friction problem would result in a retard spark scenario).

NOTE: For a friction problem to create the problem of automatically advancing the timing, which is what is actually happening via your explanation... that engine would need to be running backwards, in a Counter Clockwise direction. Yes, that's possible as when Counter Rotating propellers first cam upon the scene... a kit was designed just exactly to convert the normal clockwise running engines to rotate counter clockwise. If this scenario was somehow stumbled across, however unlikely, I would think you'd have mentioned it... you haven't... however I feel it was worth mentioning.

For that timer base to advance towards the rubber capped stop screw... the vertical throttle arm would need to be applying pressure in that direction.

Notice the Idle Adjustment Screw in the vertical throttle arm, between the throttle arm and the metal cam... Back it away so that it is not touching its stop... not touching anything. That adjustment may have been turned in by someone, BUT, the picture does not back up that thought as... in the picture, the timer-base appears to be retarded properly and the vertical throttle arm does not appear to have any pressure applied to it. However, back that adjustment screw away from its stop anyway.

That stop screw adjustment may be your only problem, but if not.......

Loosen or remove the plate that holds the throttle cable adjustable trunion in place and adjust that trunion so that it lowers the setting of the vertical throttle arm.... with the idle stop screw NOT pressed up against anything and lowering the setting of the vertical throttle arm... that should bring the rpms down.... and if so, on a flushette, with that adjustable trunion, set the idle rpms as follows:

Long shaft..........(20") = 1000 rpm
Extra Long Shaft (25"") = 1200 rpm

At the moment, I can not think of anything else that would cause that timer base to advance on its own with the engine rotating in its normal clockwise direction.

Hopefully nobody has tinkered with the adjustment nut on that weird shaped linkage between the vertical throttle arm and the metal cam that slides against the Throttle Cam Roller (Idle Timing Adjustment), but if so... the Idle Timing will need to be reset via a timing light with the scribe mark of the Cam aligned to dead center of the Roller to whatever degree the service manual calls for via that adjustment but.
 
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Excellent Joe, you said everything that needs to be said. Great job. Thanks for solving this....we hope. That stop screw doesn't look like it's backed out enough to me. A good picture is worth a thousand words.
 
The black plastic wheel on the throttle cable needs to be adjusted so thatt the arm is ppulled against the idle stop screw.----May need to adjust idle stop screw as well.
 
That could be it too but pretty obvious, unless our Bamaboater got the boat that way from somebody that didn,t have a clue. I've seen it before.....thats why they sold the boat. What amazes me is why would someone set up the idle that high to begin with? Maybe the lever that rotates the trigger is out of place. Like Joe mentioned to Bama, clockwise rotation will of course retard the timing thereby slowing the motor. Closer study of the picture indicates a near virgin motor, but that idle stop screw on the vertical lever seems to be against the stop. So when Bama pushes the trigger with the screwdriver, there is enough play to slow the motor.
 
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Hi, Thanks for all the comments a replies. And thank you Joe for the very in-depth reply. It's hard to see in the picture I don't know if y'all went to YouTube and watch the video or not but the stop for the vertical arm is backed out far enough that when I push on it to slow the idle down it's tops before I ever come close to touching the stop itself. As soon as I get home from work this evening I will be tinkering with it more. I can't tell what the previous owner may have done or didn't do. It is possible the timing is off and that the throttle cable itself may be off because it is new. I am almost 100% sure that the flywheel is rotating clockwise but I will double check on that. Again thank you so far for the help and comments as soon as I get home I will look into it further and I will keep you all posted.
 
Oh and Joe what I am pointing at is the linkage between the vertical arm and the timing base I don't know if you seen that YouTube video or not but looking at the picture when the motor is running it continuously moves itself to the right away from the stop that is on that arm and when I push it back and it idles back down I'm not even touching the stop but if I let go it's slowly opened itself back up. Hopefully that makes some sense.
 
Maybe Racer is right. The guy you got it from had cranked up the cable to get it to idle with the spark problems. Finally it died altogether.
 
That is probably correct I guess if you would have investigated a little further heater figured out the spark problem was a faulty kill switch LOL I will go through the manual. And work on adjusting the timing and setting the throttle where is supposed to be.
 
I will upload a picture. I assume this is the black wheel you are talking about? The bottom one? Also I put another video on my youtube which is linked here which shows a little better what is happening and what I am talking about.pic3.jpg. I do appreciate everyone's help and apologies for being so bothersome., https://youtu.be/QlPJ61QO7R4
 
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