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    2002 mercury 4 stroke EFI powerhead 40hp

    Stupid question of the day, Can I remove the the 40hp(4s EFI) power head and put a 50hp(4s efi)on it? The cowls would be different, other than that will the exhaust adapter plate and drive shaft mate up? Will a 60 (4s EFI)? Just wondering? Rather do this than buy a new motor
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    Mercury 40hp 2002 Four Stroke EFI

    I can't get the RPMs out of it. I just moved it from another boat to a 21' barge. The motor shutters and won't get to full RPM. I have a 13 pitch prop on it. If I get a 9 or 10 pitch, will this help it? Good compression, good plugs, good fuel, good injectors. It ran good with a 15...
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    2002 Merc 50hp 2stroke. Water flow problem

    I just put a rebuilt powerhead on this joker. Got it together, and it is not pumping water, DARN IT! I removed the lower and it seemed in order, the impeller was good. I pressure wased the block before assembly, passages looked ok. I removed the lower unit and stuck the garden hose on...
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    2002 mercury 2stroke 50hp thermostat question

    Can I just leave it out What would be the consequences?
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    Mercury 2002 50hp 2 stroke rebuild

    Serial OT161xxx. Blew a rod (#1) through the block. The 50 failed due to a rod bolt, don't ask how I know..... I found a stripped powerhead from a 60hp. It had a scored #3. I had the 60 block bored out 30 over. I have new rod bolts for this project. I am going to go through the carbs I...
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    2002 Mercury 50hp 2stk tiller safety switch

    I am converting a remote to a tiller. Where in the name of dickens does the Nuetral Safety Switch go????? The gear case is shifted by a lever on the right side of the motor (right side of boat). Help! Where does it go?
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    Mercury 50hp 2strk electrical question

    2002 Mercury 50hp 2strk #OT490xxx the 12v red wire that is in the harness that goes to the key, is it just to activate the starter selinoid? Will it kill the motor if this wire is deactivated? Or does this motor HAVE to ground the magneto wire (Yellow-black) to kill it?
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    16' Xpress Drake What engine?

    I just bought a 16' Xpress Drake (AWD) edition. I was wondering which of two motors to install on it. First option, mercury four stroke 40hp EFI. Second, Mercury 50hp 2strk. The 50 2strk is being built. It will have a 60hp powerhead bored out 30 over. The 40hp is stock. Great motor...
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    Mercury 2strk converted to 4strk

    I have a 2002 50 hp merc that is the oil injected it blew a rod :( I have this set up. CAN I change the adapter plate and make a 4 stroke out it? Just a silly idea, but can it be done?
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    90hp Mariner Knock

    Picked up a used 90hp Mariner. It is from the early 90s (OD163,,,). Compression is good and even across all three cylinders Starts up good, Runs great on Muffs including in gear. Mounted it on a boat, took it to the ramp to do a on the trailer test. Started, pumped water, shifted fine...
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    Mariner 1994 90hp Knock

    I was hoping for a couple of focused areas to look at before scratching my head. Have a 3cylinder 90HP mariner. #OD163656 I has good compress and idles just fine. I put it on a boat and took to the boat ramp to test it under a load. Basically keep the boat strapped down and throttle up...
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    Rod Bearings and bolts

    Got a mercury rebuild question. Is it ok to reuse the bearings for the crank to rod? IF they are servicable.> Second, the bolts that clamp the rod around the crank. is it ok to reuse these? Need a no nonsese answer. Thanks
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    Bore Size

    What do I need to bore to for an over sized piston? Mariner 90hp OC263xxx Standard L3 3 piston Engine has not been bored before. How big do I bore out to? I plan to use a .020 oversized piston. Do I just find the center of the cyliner hole and add .020 to the diameter? How much do...
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    Mariner 90hp- boring of the cylinders...

    I am about to undertake a project of rebuilding this 90hp outboard. Serial #OC1620xx. I am a reasonably decent machinist. I am going to bore out the cylinders on my milling machine. I am somewhat confused on the piston size......... Does this require an oversized piston or just oversized...
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    Exhaust Back Pressure

    200 Hp Optimax 1999. I have alot of the exhaust coming from the port in the cowling. Not much from the prop area unless I am covering the cowling exhaust with my hand and all sorts comes out the prop ( at Idle) I am also having problems with getting it to hole shot and plane out. It stalls...
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    optimax 200hp (1999) dies at throttle

    I have this optimax. Here's what it's doing. When its trimmed down to take off ( to get on plane) it will die. Idle is tuff at this tucked in angle. If I trim it up, it will start again, run, and do fine. BUT when its trimmed down, it dies. I have been through the vapor separator...
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