92 mercury 150

I have a 92 150 mercury 150 that would only turn 2300 rpm. I changed out the stator and switch boxes reset timing cleaned carbs. Now it will turn 2500 rpm but 5200rpm in reverse. any ideas as to why the motor wont turn up in foward?

Re: 92 mercury 150

I would suspect something is binding in the lower unit. Notice any noises when you engage forward and reverse that might seem a little bit odd? Perhaps you have a shifter cable that is in need of adjustment.

If the motor can reach 5200 rpm in reverse, but not forward, it's not the motors operation, it's something in the driveline. Perhaps you are over propped? There is much less force/drag on the motor in reverse than there is going forward.

Re: 92 mercury 150

redfury said:

I would suspect something is binding in the lower unit. Notice any noises when you engage forward and reverse that might seem a little bit odd? Perhaps you have a shifter cable that is in need of adjustment.

If the motor can reach 5200 rpm in reverse, but not forward, it's not the motors operation, it's something in the driveline. Perhaps you are over propped? There is much less force/drag on the motor in reverse than there is going forward.

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Before I replaced the stator the motor would only turn 2300-2500 in forward or reverse. no noise in the lower unit.

Re: 92 mercury 150

Is compression good?I doubt prop is your problem unless you have a 36p prop on there!I would do basic compression and spark test.Then test to see if youre dropping cylinders at higher rpms.Also may wanna look to make sure carbs are opening all the way at WOT.If not,a lync and sync may be in order(or new throttle cable).

Re: 92 mercury 150

starcraft1982 said:

Is compression good?I doubt prop is your problem unless you have a 36p prop on there!I would do basic compression and spark test.Then test to see if youre dropping cylinders at higher rpms.Also may wanna look to make sure carbs are opening all the way at WOT.If not,a lync and sync may be in order(or new throttle cable).

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compression good all cylinders, spark on all cylinders carbs clean. Original problem was motor would only turn 2300@wot. Stator was bad. so I replaced it. Just don't make any sense It runs like a champ in reverse 5200@wot and no power in forward with 2300-2500@wot.

Re: 92 mercury 150

try spraying some premix in the carbs while running in forward gear and see if it picks up, you might have a weak fuel pump.

Gotta keep throwing possibilities out there until we eliminate them all and solve the problem.

Have you watched the throttle/shift cables operate their respective linkages to make sure your getting the proper amount of movement?

I'm not that knowledgeable on outboard ignitions, but I wonder if there isn't something with the stator that was an issue originally, that is still an issue... Crossed wire? Any chance something is causing one of the switchboxes to cut out in forward?

Could be that you ALMOST got it fixed, but something minor is eluding you, like a ground or something rubbing because it wasn't put back EXACTLY the way it was designed. Not being there, one can only speculate.

Re: 92 mercury 150

Is this a NEW problem on a motor that you have had for a while?

OR

Is this motor NEW to you and has this problem?

Have you or someone else, had the prop off and dropped the thrust washer?

In Forward the prop will grind itself into the casing, causing LOTS of drag, yet seem perfectly fine in Reverse.

Pull the prop, check the thrust washer, look for any contacting marks on the prop and gearcase.