1991 200 hp XP - rough idle and engine vibration at idle/no wake speed.

[evinrude_dude]

I've got this motor on a 1991 Stratos 289FS. I bought the boat used in 1998. This boat doesn't have much of a hole shot but runs great once up on plane. I can run in the low 60's with the boat fully loaded with gear and two adults. <br /><br />The problem is that the motor has an annoying vibration at idle and no wake speed. I don't think the problem is related to the anything in the lower unit or the prop. A year after I bought the boat I hit an underwater obstruction. The prop had to be reconditioned and the lower unit had to be rebuilt. The vibration problem existed before and after this incident. <br /><br />The dealer I bought it from gave me all of the original documentation for the boat and motor. The original owner's customer satisfaction survey was in the papers. The original owner also mentioned the rough idle and vibration problem. Apparently the problem existed from day one when he bought it new in 1991. I've asked the dealer about the problem and they told me it is the nature of this motor to run this way. Does anyone<br />out there know if this is true or not? <br /><br />Thanks,<br />Roger......

 

[Dhadley]

Re: 1991 200 hp XP - rough idle and engine vibration at idle/no wake speed.

My 91 looper runs very smooth. Even the highly modified looper on the race boat idled great. The modified motor was balanced so thats not a good comparison. But the 91 is stock and idles smooth even in gear with a 28" 4 blade prop.<br /><br />Because you mentioned a bad "holeshot" I'm thinking it has a lot to do with being deep in the water at idle. The wall of water in the exhaust can will plug up the exhaust to some degree. There are ways to relieve the exhaust (without making it loud) to help the idle. There were some bulletins out about that years ago. Your dealer should be able to help you with that.<br />Or try raising the motor. Depending on the RPM's you may gain a little performance also.<br /><br />Good luck!

 

[evinrude_dude]

Re: 1991 200 hp XP - rough idle and engine vibration at idle/no wake speed.

How high would you recomend I go with the motor?<br />I've got a 6" jack plate on it now but I don't think the motor has ever been moved up or down... at least it hasn'e since I've owned it. <br /><br />Thanks.

 

[Frank Martin]

Re: 1991 200 hp XP - rough idle and engine vibration at idle/no wake speed.

often overlooked detail of a poor idle is the recirculation system the hoses can be routed wrong ,valves bad ,castings with flashings in them ,the whole system has to work rite to have a good idle

 

[hondon]

Re: 1991 200 hp XP - rough idle and engine vibration at idle/no wake speed.

Frank is right , recirc are often overlooked in idle problems but easily troubleshot by you the operator.Next time out ,when idleing ,trim the motor out to full trim and see if you notice a substantial change in idle quality .If so then recircs are suspect.Dhad is also right on.These things need to breath so raisiing the motor a hole might not be a bad idea.You will need to monitor things when you do this and you can continue to raise the motor until you begin to ventilate in a turn or notice that you are over reving.

 

[Dhadley]

Re: 1991 200 hp XP - rough idle and engine vibration at idle/no wake speed.

You have a good baseline - holeshot time, water pressure, top RPM's and speed. The jackplate makes it easy. Go up an inch or so at a time and your water pressure and / or prop will let you know when you have gone far enough.<br /><br />Also make sure you dont have loose flywheel magnets. Look up from under the flywheel and make sure the magnets are evenly spaced and cant be moved by hand. <br /><br />Keep us informed!