Stator rotation 90 hp 1995 3 cyl Mercury

[sorensonrg]

I have the shop manual for my engine 1995 90 hp OG151664. It shows the proper rotation of two types of stator, mine is the large rim but it's installed in the small rim position (should be rotated one position CCW per the manual). Will this cause a timing problem? Boat runs great on muffs but can't get on plane in the water. Great RPM's in reverse.

Also tested my trigger and found two leads were over 1000 but one was 700. I'm now very familiar with my engine but am still a skilled novice at boat motor repair (impeller is easy, engine rebuilt daunting)

 

[Dave1027]

Re: Stator help please 90 hp 1995 3 cyl Mercury

Re: Stator help please 90 hp 1995 3 cyl Mercury

Have you checked the timing with a timing light?

Spark gap tester?

 

[sorensonrg]

Re: Stator help please 90 hp 1995 3 cyl Mercury

Re: Stator help please 90 hp 1995 3 cyl Mercury

Attempted to check timing with borrowed light, didn't work out too well. The light would only flash when I rotated the advance dial to approx 20 degrees so I had no good indication except that it did flash and numbers could be read. Need to try again with another light, hard to borrow these days.

Spark gap was tested and all plugs were strong. Compression is equal and in spec for all cylinders. Had a tech do that for me so I don't have the numbers, my guage was way off of his but both of ours showed all cylinders where equal.

 

[j_martin]

Re: Stator rotation 90 hp 1995 3 cyl Mercury

I don't know the engine. Does it have a separate trigger? If so, the stator position makes no difference. Timing comes from the trigger.

 

[sorensonrg]

Re: Stator rotation 90 hp 1995 3 cyl Mercury

Yes, the trigger is seperate. I ran into the Mercury shop owner today and he agreed with the manual, the rotation makes a diference. Attempted to pull the flywheel today, but sheared on bolt instead; spent the next two hours extracting the bolt. Note to self.....by high strength bolts tomorrow!

I tested the trigger again today with two meters to ensure the readings were accurate. The white and purple wires tested above 1000 ohms to the white/black, but the tan wire tested 700 ohms. Each one tested infinite to ground.

Ran it today as well on the trailer in a test pit at the local boat store (it's good to know people). Mechanic wasn't there but the test allowed me to run under load. She was strong up to 3400 rpm but wouldn't go past that with the prop in gear. She'll run all the way to with the prop disengaged. Nice and smooth to the point the shop owner walked up and asked why I was concerned as the boat sounded good. Once he got in and ran it himself he agreed that I wasn't getting the top end that I should.

I did choke the motor at 3000 rpm several times (by pushing in the key) and she started to flood out and drop rpm's each time so it's not a fuel supply issue.

If I get the flywheel off tomorrow I'll rotate the stator to the manual position and retry. I'm concerned about the trigger's readings. Maybe that low reading cylinder isn't getting the spark at high rpm's?? Guessing here.

Thanks for the input, I'll keep posting my outcomes.

 

[Faztbullet]

Re: Stator rotation 90 hp 1995 3 cyl Mercury

It only that way so wiring doesnt get pinched, junky red stators......

 

[sorensonrg]

Re: Stator rotation 90 hp 1995 3 cyl Mercury

Got the flywheel off last night late and saw that the stator had arrows indicating three aft positions for various motors. They had the arrow for a Mercury pointing aft but it should be the arrow for the Sport Jet/Mariner (mine is not a jet engine but that's an option - my factory manual has repairs for both). I'm rotating this am and will hopefully go boating! Will post.

Answer to the first question on my motor - rotation of stator does matter.

 

[Laddies]

Re: Stator rotation 90 hp 1995 3 cyl Mercury

Your first question was. "Will this cause a timing problem?" Two of the best mechanic on the site said NO! They we spot on, one even told you the reason to change stator position was for the wire routing, absolutely correct. So in your last post you changed the Question to "Answer to the first question on my motor - rotation of stator does matter. Bet they will stand in line again to be smart mouthed.

 

[sorensonrg]

Re: Stator rotation 90 hp 1995 3 cyl Mercury

Whoa. No disrespect was intended,I was sharing info I discovered while investigating my engine. That's a common theme in this forum and a critical comment I often see when folks ask for help, get it and then don't share the results.

My results turned out not to be good. I did then rotate my stator one position, started it on muffs and the motor backfired once, and sheared the flywheel key. I can't do anything until I get a new key from the Merc dealer tomorrow. Not sure what happened with the backfire but I'm moving the stator back to it's original position where I never had a backfire and start the search anew. If position doesn't matter I don't think that would be a bad move.

My comment was intended to summarize what I thought I determined from reading the stator. Applogize if I appeared to fly in anyone's face, not my intent by a long shot. I even stated that I was out of my comfort zone, not the stuff of a smart mouthed person. I hope that clarifies my intended purpose for the statement. I would like to continue with this forum, it's been a huge source of learning for me and I hope I can share some info that others might find useful as well.

 

[sschefer]

Re: Stator rotation 90 hp 1995 3 cyl Mercury

On certain motors, stator postion needs to be correctly aligned with the flywheel magnets. If you are having performance problems then it could well be weak spark voltage. Rotate it one screw hole in either direction and retest.

You'll find a number of references to this in the cdi electronics trouble shooting guide at www.cdielectronics.com. Please go download it and read it, it will remove all doubt.

Hope that helps.

And no, it wont, can't, will not, never happens, etc... effect timing.

 

[sorensonrg]

Re: Stator rotation 90 hp 1995 3 cyl Mercury

Appreciate the reply, it might explain my misunderstanding. I've read elsewhere in other posts that rotation of the stator may change performance and I INCORRECTLY thought that meant a change in timing and was quite confused. A few of you have UNconfused me now as far as the stator having nothing to do with timing, a good start. Now I'm asking for a bit more education please.

Could there be any connection between my rotating of the stator and the backfire that sheared my flywheel key? I wasn't able to reinstall tonight so I'll be able to confirm that I'm back to where I was with a running engine without the top end. Does the stator only produce AC power? I understand that the flywheel magents are aligned around the shaft by the keyways on the shaft and flywheel, not sure I understand how the alignment to the stator matters. Last question, how does the trigger fit into the equation? I see that it has a wire for each coil and a common but that's about it.

Appreciate the help. I'm working on pics of the stator and trigger.

 

[sorensonrg]

Re: Stator rotation 90 hp 1995 3 cyl Mercury

Learning continues! Learned another important lesson, don't install flywheel "snug" so its easy to remove when you play with the stator. I sheared my key since the flywheel put all the stress on it, almost died when I read in the manual that I should have tightened to 120ft-lbs! New key and properly tightened flywheel nut got her running up to 3000 again. New twist, I was running on the trailer at WOT and she started to surge from 3000 rpm to 3500 and almost 4000 a few times without input from me. I'll check the fuel system again as my new primer bulb is not getting tight running or not running. Going to check pickup in tank to ensure it's not clogged and tank venting then on to the carbs. A couple of good write-ups on clogged carb vents and float issues will help in the trouble shooting. If this doesn't work it's back to the trigger and stator. My DVA test of the stator during cranking (green/white to white/green) was a bust, no meaningful number greater than 2 registered during cranking. Was set to voltage and had CDI DVA adaptor in correct plug locations. Ohms read 0.74 between same wires, used two meters to check. Starts great and runs well to 3000. Pointers and test recommendations would be appreciated. Thanks