87 115hp inline six wont rev above 1200 rpm in gear

Ok, I adjusted the idle today in my drive way and got it running good. It revs to redline in fast idle, and also when in gear in the drive way. Took it to the lake, it idled good. Went to take off, and it died at anything over 1200 rpm. If I raised the prop out of the water, it would go all the way to red line. Anyone have any ideas? The highspeed stator was replaced about 8 years ago. I have heard that merc. motors are notorious for them. Am I headed in the right direction?

Re: 87 115hp inline six wont rev above 1200 rpm in gear

Ya i have the exact same problem with the same motor. my post is titled 115 blue stripe hit's a wall @ 3000 about 12 posts behind this. A bunch of ppl including myself think it's the stator, but it could be the trigger.

Re: 87 115hp inline six wont rev above 1200 rpm in gear

first off never rev a motor out of the water. It may be that your missing spark on a few cylinders, if so it could be a stator, trigger, switch box, coil, etc. Assuming it's a spark problem, you could find the one, 2 or 3 that aren't firing with a timing light and start switching wires from plugs that are firing to find out which part is bad. Or the proper (and my suggestion) is to go here http://www.cdielectronics.com/downloads/troubleshooting guide/
and read how to test your electrical system. You'll need a DVA adaptor for your tester, make one for 5 bucks or buy one for 30 bucks.

Also check your compression and make sure your getting proper fuel.

Re: 87 115hp inline six wont rev above 1200 rpm in gear

Why shouldnt I rev the motor out of the water? I had a hose and adapter on the water intake in the driveway, and in the lake I just lifted it until the prop was throwing water. The intake was still in the water. It seems that it is the load placed on the prop that makes the difference. I know that an engine needs more fuel to produce more torque, but surely if it was a fuel problem there would be some symptoms at high revs without the load. The motor is not missing on any cylinders. It sounds exactly like it has for the past 23 years. I agree it is probibly an ignition problem. How difficult is it to replace a stator? And where might it find one for a good price?

Re: 87 115hp inline six wont rev above 1200 rpm in gear

http://www.cdielectronics.com/downloads/troubleshooting guide/Mercury 6 Cylinder.pdf That's the correct link from the link that arsenalpsu just posted for our motor. Prit it and look @ the instructions for will not accelerate beyond 3000-4000 and follow that. and thank you for the link once again arsenalpsu thoes are very good instructions. You shouldn't rev your motor out of water because theres no load on the prop and it's very easy to over rev and cook it like a turkey.

Re: 87 115hp inline six wont rev above 1200 rpm in gear

Thanks everyone! Ill get to work tomorrow!

Re: 87 115hp inline six wont rev above 1200 rpm in gear

If you adjusted the idle screws closed for a better idle try turning them out 2 turns from lightly seated.

If the idle is too lean it will idle ok but die out lean on transition from idle to open throttle.

Re: 87 115hp inline six wont rev above 1200 rpm in gear

king_butt_head said:

You shouldn't rev your motor out of water because theres no load on the prop and it's very easy to over rev and cook it like a turkey.

Click to expand...

Yes, and without you even doing a thing:
http://forums.iboats.com/showthread.php?t=430437&highlight=runaway
The engine can rev and not stop even though you killed spark. Only way to stop it is cut fuel, air... or wait until it rips itself apart.