1988 XR2 150 idle/ running problems.

[Conn]

serial OB221010 Merc 150 XR2 on a 17.5' fish and ski. <br /><br />idles rough, motor shakes around, smokes a lot, misses sporadically at idle and seems sluggish between idle-2500 rpms. seems to run well at full throttle, but still seems to lack a little top end. i don't think the motor is getting to it's max RPM. <br /><br />it will get up on plane pretty quick, but it hesitates for about three-four seconds after i mash the throttle. i've only seen the engine go to about 4500 RPMs at about 52 mph. it's got a 23 pitch? prop. <br /><br />trolling around at 1000-1200 rpms, with steady throttle, the engine speed seems to sound like it's increasing and decreasing off and on, varying by probably 200-300 rpms. <br /><br />i've....<br />1.cleaned the carbs pretty thoroughly before i purchased a manual<br />2.i bought a fuel pump rebuild kit but have yet to install it. <br />3.Changed the plugs (BU8H)<br />4.Seafoamed<br />5.New fuel filter<br />6.Drained the fuel tank completely and put fresh gas in. <br /><br /><br />i searched and someone mentioned bleed valves being sticky? i had considered rebuilding the fuel pump and taking the carbs back off and re-checking the float levels. <br /><br />i don't get a lot of time to be on the water when i go, so i'd like to get this thing running right so I don't have to worry about it so much. it runs, but i don't think it's running right. <br /><br />conn

 

[KCLOST]

Re: 1988 XR2 150 idle/ running problems.

Sounds like you have lost spark on one or two cylinders... Test for spark and let us know...<br /><br />Use a spark gap tester set at 5/16" gap...

 

[Conn]

Re: 1988 XR2 150 idle/ running problems.

what would cause an off again, on again spark? stator? it doesn't seem like it's missing a LOT, just occationally it will sound like a miss, then it smooths out a little. but the motor always shakes back and forth about an inch or two when idling around through the no wakes, even when it's not got the "miss" feel to it. <br /><br />i've got a spark tester on the way and it won't be here until this afternoon, i'll put on the ear muffs and try it out when it gets here.

 

[studlymandingo]

Re: 1988 XR2 150 idle/ running problems.

where did you order your spark tester from?

 

[Conn]

Re: 1988 XR2 150 idle/ running problems.

Napa. All six were emitting nice blue, consistant spark between all of them. i tried to get as close to 5/16 as I could and probably got a little over, but i figured a little more should be better than a little less. if it'll jump 1/2", then it should jump 5/16.

 

[Conn]

Re: 1988 XR2 150 idle/ running problems.

UPDATE. <br /><br />put the earmuffs on and fired her up just after a fuel pump rebuild (just for precaution, and it was cheap and already here) let it idle for 5 minutes, idled smooth, then started running rough, almost dying. throttled the engine up to 2000, ran for a min or so, then idled back down and ran somewhat smooth. throttled back up to 2000, and after it sat there for a sec, the RPMs started to fluctuate between 2000-2250. <br /><br />i checked the butterflys on the carbs (probably a .010 reveal on the top, rather than a .005 on the bottom two) since the top carb was a smidge off from the others, i reset it back to where it matches the rest, and i'm going home for the evening...<br /><br />what should be my next step? should i take the carbs apart to check the float level? then doublecheck to make sure they are good and clean? I just cleaned them, but may have missed something? <br /><br />could the oil mixture be causing it to do this? idle, then want to die, then a fluctuating "steady" throttle? I'm lost at this point. <br /><br /><br />edit: it's still smoking a lot. i ran off every 'skeeter within a mile radius. <br />thanks.