removal of flywheel

remant333

Cadet
Joined
Jul 20, 2003
Messages
16
Hello, just had motor in shop, got it back with grinding noise(not there before) after having carb rebuilt and another drive shaft and foot put on. The mechanic says he thinks the bearings are bad. never made this noise before.<br /><br />anyway, have checked to see if cap loose, seal broken but everything seems dry- no oil or gunk anywhere under flywheel. anyway I want to remove flywheel and check to see everything is tight. what size gear puller do I need for flywheel and is it possible to remove flywheel and keep the timing as it is?<br /><br />History/// 1973 200merc 20hp. Motor previously sat up for eight years, foot blew apart and broke houseing. After long search found a complete lower unit for $122.00. Paid $201.00 for carb rebuilt and foot attached to old lower unit, also new seal put in foot/prop. No history of noise before having this work done. mechanic is new to area, self employed- claims bearing most probable cause of noise and loss of power on top end. mechanic left motor to sit for a week but did no more work on it nor searched out noise.<br /><br />We put the boat back in the water and took off with throttle wide open. With weight of myself and son, the boat accelerated fine and planed fully on top of water. we then added mother's weight to boat and boat would not plane though it previously planed fined with all of us in the boat. I use to use a six gallon tank with this motor, now am using temporarily a three gallon tank, can this make a difference in lost speed.<br /><br />As this noise is new is it possible that there might have been damage to upper gear case? It's hard for me to beleive the bearing just all of a sudden starts with a grinding noise that comes and goes. thanks for your help.<br /><br />so, I need instructions to remove flywheel and tool I will need and any thoughts you may have.thanks again
 

stocky

Seaman Apprentice
Joined
Apr 24, 2002
Messages
43
Re: removal of flywheel

I am not familiar with your motor but I have heard of cases where the magnets that are attached to the inside of the flywheel come adrift. Apparently you can reglue these back to the flywheel if they are not damaged.
 

andrewkafp

Lieutenant Commander
Joined
Mar 15, 2003
Messages
1,668
Re: removal of flywheel

I'd be a bit more diplomatic about the "Mother's weight" comment...<br />Hope you have a warm gararge out there.. :D :D :D
 

remant333

Cadet
Joined
Jul 20, 2003
Messages
16
Re: removal of flywheel

Hey unicorn, I wasn't referring to my mother, but rather Mama being my sons Mother, you know-"Son-- go and pick up mama at the dock. As for mama's weight I am the heaviest of all at 200lbs. Hope you weren't offended, sorry about that
 

andrewkafp

Lieutenant Commander
Joined
Mar 15, 2003
Messages
1,668
Re: removal of flywheel

Nahhh!!!<br />I was only joshin' about the reference of your son's mother (Your partner) and the consequences of mentioning her specific gravity ..<br />And the effect of the planing...<br />"we then added mother's weight to boat and boat would not plane "<br />She might just be reading this post :D
 

The Marine Doctor

Commander
Joined
Jul 25, 2003
Messages
2,177
Re: removal of flywheel

Run the engine without the rewind on top...sometimes you will hear rattles come from it...its hard to distiguish what the noises actually are and where they originate.<br /><br />Also....what is the pitch of prop you have...is it the same as the old one?<br /><br />TMD
 

remant333

Cadet
Joined
Jul 20, 2003
Messages
16
Re: removal of flywheel

Hello marine doc, thanks for your imput. Prop is the same.<br /><br />You said, "run the motor without the rewind on top"? How do I start the motor without the pull cord? <br /><br />The noise in the beginning came and went ,no matter the rpm, now it is a constant grumble. mechanic thinks it might be a bearing? while others think I should remove flywheel and check magnets ect and make sure no screws have backed out. I bought a gear puller last night, still waiting for someone to tell me how to pull off flywheel and put back without changing the timing? guess I will just make marks on engine and flywheel and put back after I examine.<br /><br />Anyway, would appreciate any info or ideas or instructions you may have. mechanic thinks that it may be bearings concernig the pistons??? I am not sure what he was referring too? would this make the engine loose power in pushing boat though rpms still stay high?? Boat ran fast with 500lbs of human weight but now only planes with 300lbs though engine rpms are the same. thanks again for any help
 

greasemonkeyozi

Petty Officer 1st Class
Joined
Jul 16, 2003
Messages
282
Re: removal of flywheel

If bearings was to go out on your pisons, many unusual noises will be heared, however, you say the noises you are hearing are coming from the top of the engine, around the flywheel area.<br /> I have had a similar problem with my motor, and found that the grinding was coming from my flywheel rubbing against the top of my motor cover. If the flywheel is not torched down correctly, it may not be seated down far enough on the motor itself. Try taking your flywheel off and look for sighns of your flywheel scratching on something, and also do look for any magnets loose. Dont worry about timing, there is a device under the flywheel called a stator which holds your timing. You can also take that off, just dont adjust anything. <br /> Ok. you wanna know how to take your flywheel off. Its real easy if you have an air compressure and an impact gun and a pulley puller. If you dont have any pnumatic tools, you at least need to buy some pulley pullers. Of course you know to take the lock nut off from the center. Good luck if you dont have an impact gun. You do need a puller though. You can buy one at any parts store, every guy needs to own one anyways, their not expensive. DO NOT attemt to remove your flywheel without a puller, you will warp it.<br /> OK. loss of power. You said that you had your carborators rebuilt. That sounds like a minor fuel problem or timing is off. Any time any major work is done or new parts installed to your motor, timing is a must. Your shop manual will tell you this. Did your mechanic reset the timing? Did he properly set you floats in your carborators? Did he adjust the fuel flow? Did he replace spark plugs? If so, are they the right heat range? Is your fuel and oil mixture right? <br /> <br /> I own a 77 merc 70 hp. motor and I have to work on it myself and everyone elses' problems because boat mechanics are just too expensive.
 

greasemonkeyozi

Petty Officer 1st Class
Joined
Jul 16, 2003
Messages
282
Re: removal of flywheel

Oh yeah, you also said that your mechanic replaced a piston. If he did, run a compression test on all your cylinders to see if his work was done right. Loss of compression means loss of power. It being a merc. your compression should around 135 psi. Just check all of them, they should all be the same. If one is lower than the other, thats your loss of power.<br /> Again, you can buy a compression tester at any local parts store.
 

remant333

Cadet
Joined
Jul 20, 2003
Messages
16
Re: removal of flywheel

thanks Chris for all the info. As of yet i do not have the shop manual and can't afford one this moment. the mechanic who worked on motor did not put piston in though he did say he thought noise and loss of power was from a bad bearing, don't know which bearing. He did not do a very good job, changed ground wire from power pack but left it completely loose in its connection. when we picked up motor some parts of engine was not even put back together, he said he was too busy to fool with motor. to say the least we were dissapointed with him and wondered why did he do the work on the motor if he knew we needed new bearings? anyway, can't afford now to go to another mechanic, as you say-way too expensive.<br /><br />I do have a pulley puller but no air wrenches or compressor, instructions on top of flywheel say to remove two screws(opposite each other) then use pulley puller, but says nothing about center large nut, but it seems logical this large bolt must come off the shaft. Anyway, how can i get the bolt off to remove flywheel if flywheel keeps turning?? which way does bolt come off--counter clock wise or clock wise?? it's been 30 years since I pulled a flywherel off and that was on a 68 pontiac firebird for a timing chain. <br /><br />thanks again for your help, not sure if noise has anything to do with flywheel, I pulled plugs and pulled started cord but could not detect noise, only when running can I hear noise and I can't make out where the noise is coming from because the motor itself is loud.<br /><br />As to whether mechanic adjusted carbs correctly or linkage or timing, we have no idea. he did change plugs and now I have jap plugs (ngk). Motor starts usually on one pull though. thanks again.
 

greasemonkeyozi

Petty Officer 1st Class
Joined
Jul 16, 2003
Messages
282
Re: removal of flywheel

Just like anything else with screws, nuts, and bolts. Righty Tighty, Lefty Loosey. To remove the center nut, or bolt, turn it counter clockwise. Yeah, since you dont have any pnumatic tools, you gotta find a way to wedge that thing to keep it from turning while you break that center nut loose.<br /> I'm normally good at finding ways to do things like this by not having the needed tools, but I have to see what the situation is. Try having a friend, a strong friend hold that thing with gloves or a towel to get a good grip on it to keep it from turning while you break that nut loose. Then again, look for somewhere to maybe place a screwdriver to wedge it in place. <br /> Theres shortcuts and tricks for almost everything. Dont let a small boat motor kick you in the a!!<br />I'll keep posted on your problem and if you need any more advise, holler back. Let me know how it goes.<br /> P.S. Do Not take no more than those 2 bolts that face each other off. There is some timing stuff mounted under the flywheel itself that does not need to be removed. Trust me.
 

greasemonkeyozi

Petty Officer 1st Class
Joined
Jul 16, 2003
Messages
282
Re: removal of flywheel

Oh yeah, try looking on ebay for a manual. You would be suprised at how cheap. Im talking around the single didget.
 

remant333

Cadet
Joined
Jul 20, 2003
Messages
16
Re: removal of flywheel

thanks again for the advice, I tried all sorts of things to wedge flywheel but still the torque has beaten me plus the nut has been wrenched before and is beginng to round off. I took the motor off the boat and put the nissan 8hp back on it. I can run this motor all day full throttle day after day and still no problems. anyway I can atleast do a little shrimpimg before season ends.<br /><br />As for the merc I believe the main bearing is the problem and i don't think I myself will be able to change it out. Everything under the flywheel seems tight, magnets included. the noise is now non stop. thanks for your help, I am going to go to ebay where i got the lower unit from and look for a manual( that's a good tip). sure appreciate you taking the time to help me. thanks again for your reply
 
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