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1989 3.0 OMC Cobra won't go over 3200 rpm's???

R

Ron61

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I just purchase my first OMC powered boat and took her on maiden voyage today. Motor starts and runs smooth. Boat won't plane out or go above 3200 rpm"s. Trim all the way down. Shifter shifts but seems to hang up at times going back into neutral from drive. Also, as embarrassing as it is, I made the mistake of leaving earmuffs on lower end when I first took off. Would this ruin impeller and cause the rpm problem??
I know, stupid right!? Rough day! Boat idled and ran fine at lower rpm and come in on own power. Any suggestions or input would be greatly appreciated.
 
Update... opened and inspected impeller, still in great shape, Luckily! Also spray lubed the linkages. Shifting was stiff and troublesome before but feels much smoother operating now. Hoping that may have been cause of lack of rpms. Hope to be in the water in a day or two. Thank you to those who viewed my post.
 
Hi Hystat,
Thanks for the info. Yes, I just got the boat, a 1989 Citation 1900CC with 3.0 OMC Cobra. I took it out for the first and only time so far this past Sunday. When I opened her up to full throttle it would go to 3100-3200 rpms. The boat would stand up but it would not plane out and it felt like the motor was struggling like trying to pull a skier. I was under the impression that top end for this motor would be 4200 rpms. Motor idles smoothly and runs well at low rpm.
I haven't had the distributor cap off yet so not sure if it has points or not.
 
Check throttle linkage, choke, clean flame arrester, try running with doghouse open in case an exhaust leak is feeding the engine exhaust instead of good air.
Then read about the ESA at that link and you'll see how it interacts with the ignition. If your ESA is not the issue, you want to remove the points and check the advance weights and springs underneath the points plate. Common for 25 year old weights to be gummed up and not advancing the spark. And the boat won't plane without that timing advance.
Then onto things like fuel system and a waterlogged hull investigation.
Then drive ratio, propeller, flapper jammed in exhaust.

There are actually about 2 dozen things that can cause your symptom. Need to check a few of the more common things and cross them off the list. And make a list - it really helps.
 
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Many Thanks Hystat. I will definitely start that list. Would it be advisable to use WD-40 on the weights or is there something better to use?
 
some solvent like varsol or just electrical contact cleaner or brake clean, then oil them with some engine oil.
WD-40 tends to leave a sticky film when it sits for longer periods of time.
 
Good to know, Glad I asked. I would have gone and created more of the problem that I'm trying to cure. Many Thanks.
 
Thanks for the input Captain Peter. That was the first thing I double checked on the water. I have been following Hystat's suggestions. Used electrical cleaner under points cover plate, lubed the weights with clean 5-20 oil, got new cap, rotor, points and condenser, cleaned flame arrester, changed spark plugs, lubed linkage cables, greased gimble bearing, and changed gear oil in lower end so far. Plan on spray cleaning carb with gumout next time I get her in the water. I will post an update on on my results.
 
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