To rebuild or not to rebuild? What a F@&%ing question!

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grnwtrcruzn
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To rebuild or not to rebuild? What a F@&%ing question!

Post by grnwtrcruzn » Mon Oct 25, 2010 3:56 pm

So after purchasing a boat recently with a good ole 50hp nissan with I was told had good compression (have since learned not to ever trust some ones word), it turns out good compression to him meant 0 yes ZERO. :x
I was fortunate enough to come across a a 90 hp nissan at the same time I found out there was no compression. This is now installed and working great :) but now I'm wondering if I should go ahead and rebuild the old 50 to try and re-coup some of the costs. I'm not sure that even purchasing on of the rebuild kits would be worth it due to their fairly high cost not to mention what sort of neglect this engine was probably subjected to! So I'm wondering what others would do rebuild or scrap the thing???

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Norca
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Re: To rebuild or not to rebuild? What a F@&%ing question!

Post by Norca » Mon Oct 25, 2010 5:05 pm

I would open it up first, and have a look at it.
It could be something as simple as a broken timing belt. ( If Your 50hp have one. )
I don't know much about outboards, but no engine would wear out until there is zero compression.
At least check it out before spending any money, or throwing out a perfectly good engine with a simple to fix problem.

grnwtrcruzn
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Re: To rebuild or not to rebuild? What a F@&%ing question!

Post by grnwtrcruzn » Mon Oct 25, 2010 5:16 pm

Unfortunately, it's not that going to be one of those easy fixes. As soon as I bought the boat I took it to an outboard shop to have them look it over before I put it in the water; since I really hate paddling and hadn't done enough sailing to be certain I could make it back. When the spark plug was pulled there where metal shavings jammed in it :o and the piston cam be moved around just by the tips of my fingers. They told me it would need a rebuild. Iwas thinking of doing it myself just not sure it would be worth the time/money.

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Norca
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Re: To rebuild or not to rebuild? What a F@&%ing question!

Post by Norca » Mon Oct 25, 2010 6:21 pm

Ouch !
Metal shaving are usually not good>
If you take it apart, you will find out how badly the cylinder is damaged.
If it's not too bad, it could be possible to bore it and install a oversize piston.
My son bought a dirt bike a few years back. It had Zero compression, and the seller told us it had a seized engine.
He bought it, took it apart and sendt the cylinder off to bore it up.
It came back with a new piston. total cost 100$
He payed 100$ for the bike. He sold it 4 years later for around 1000$
If it was me, I would take it apart to have a look, it could be good, or it could be wery bad, but it's worth it to take it apart to have a look.
Good luck to you.

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kmclemore
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Re: To rebuild or not to rebuild? What a F@&%ing question!

Post by kmclemore » Mon Oct 25, 2010 8:28 pm

Well, popping the head off is an easy thing to do and will likely tell you all you need to know about how bad the damage is. Look for piston that has had the top cracked off, burned, etc... also you'll be able to see if there's a thrown rod and if there's significant damage to the cylinder walls. And besides, popping off the head will not devalue the engine, when the current value is pretty much nil (i.e. it's only usable for parts now anyway, and having the head off won't impact that).

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dennisneal
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Re: To rebuild or not to rebuild? What a F@&%ing question!

Post by dennisneal » Tue Oct 26, 2010 10:55 am

I agree that you don't have anything to lose by taking the head off the motor and taking a look inside.

Just remember to take good notes, or photos, of every part before you remove it, so you'll know where its supposed to go. Taking things apart is fairly easy. Putting them back together is usually the hard part. Its frustrating to have a few tiny things left over when you think you're done.

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restless
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Re: To rebuild or not to rebuild? What a F@&%ing question!

Post by restless » Tue Oct 26, 2010 1:52 pm

don't be shy to give the bolts a good sharp wack with a small hammer.. they can weld in over time and sheared bolts can really ruin your day!

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puggsy
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Re: To rebuild or not to rebuild? What a F@&%ing question!

Post by puggsy » Wed Oct 27, 2010 4:31 am

Try applying some heat to the bolt heads...even steel into alloy, which surely will be seized...
The heat will cause the metal to expand and hopefully free them up...then soak for a couple of days with C.R.C. lubricant..or even diesel fuel oil...this will work itself into the thread...but it does take time...

grnwtrcruzn
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Re: To rebuild or not to rebuild? What a F@&%ing question!

Post by grnwtrcruzn » Thu Oct 28, 2010 1:21 pm

Sounds like it's time to get greasy. I'll keep my fingers crossed. Thanks for the help!

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TexasDan40
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Re: To rebuild or not to rebuild? What a F@&%ing question!

Post by TexasDan40 » Fri Oct 29, 2010 8:31 am

Have you thought about finding some highschool student looking to make a little cash?

You could play supervisor. At $10-$20 per hour plus parts, you get a good working motor for $100-200 and sell it for $1000.
New the 50HP Tohatsu costs about $5100 plus installation.
Good luck.
Te :macx:

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Divecoz
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Re: To rebuild or not to rebuild? What a F@&%ing question!

Post by Divecoz » Fri Oct 29, 2010 9:06 am

This could be a good time to test or improve your skills? IF ....this kind of thing is of interest to you or IF ....you enjoy these kinds of endeavors.....
Knowledge is Power and you stand to gain a lot of it , if you do not already possess it ....
There is more than a lot of information on the Internet , to help you along , should you so desire it.
I am still in the process of a Total Renovation of a 1970 MGB and have garnered a lot of help and information from just such sites..
Personally and not knowing your situation, I would refrain from looking at this as a potential profit maker. I would look to be gaining very useful information and skill. You state you now own a similar motor and it can do nothing less than afford you a knowledge base for future endeavors ..
IMHO......... give it a go. You really have very little to lose( its now worth about ZERO$) and you have a lot to potentially gain...

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Re: To rebuild or not to rebuild? What a F@&%ing question!

Post by vizwhiz » Mon Nov 01, 2010 11:05 pm

Something to mention - head bolts are usually considered "strain bolts" - they are made to stretch under load, and as such, can usually only be used once. Now I say "usually" because (a) when you're in a pinch you do what you have to do and things can often work just fine even though they aren't to "factory spec", and (b) I've replaced many head gaskets where I've re-used the head bolts and the motor ran just fine. (none were on outboards, however)

The reason I mentioned it is that outboards tend to be high power-to-weight ratio, lightly-built motors (not light-duty, built to weigh little) using alloys and such, and the head bolts and other fasteners and items like them can sometimes be more specially designed than an older cast-iron-block motor that uses regular off-the-shelf bolts and nuts.

I will defer to others on here who have rebuilt outboards and can attest to whether it is an issue, but the trouble can come when trying to get the head tightened back down evenly and with proper torque to make sure you don't blow a head gasket... :(

But I agree - you learn a TON of stuff (tonne?) from undertaking a project like that - even if you finally give up and throw it all in a box and haul it to the junk pile...it is definitely worth the effort if you are half-way inclined to try! Couple old tricks... (1) masking tape and marker - tag all the wires and hoses and even small covers and such with which end goes where, what it was connected to, up/down, or something that will help you get it back in the right way. Digital pics can be useful now if you'd prefer. (2) As much as possible, if you take a bolt/bolts out to remove a part, screw it/them back in the hole/holes and leave them where they belong...especially if there are different size bolts used on the same part (long bolts on one side, short bolts on the other, etc.) Sometimes, this by itself can help you figure out where something goes (that bolt is long, so the part must be bigger than this one I'm holding). :idea:

Have FUN, even if there are parts left over... :D

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Catigale
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Re: To rebuild or not to rebuild? What a F@&%ing question!

Post by Catigale » Tue Nov 02, 2010 4:54 am

Learns tonnes and have funne too!

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Divecoz
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Re: To rebuild or not to rebuild? What a F@&%ing question!

Post by Divecoz » Tue Nov 02, 2010 10:55 am

Vizwhiz are you me under another name? ( that should start the rumor mill going :D ) But I have been following your post and it appears we enjoy doing much of the same things and YOU even already live within about 100 miles of where I, want to move , if and when finally........I sell this house!
Yes I too have reused head Bolts on Gas Engines in a pinch or when the compression level was low.. Just take you time , do it in the order specified in the manual and use a good /decent torque wrench..
I too have never done this on a Big Outboard Motor. But I did on a small 1983 6HP Evinrude Twin. Some MORON ( me :( ) dropped her off the back of the dink , into salt water...Did you know there is often enough air captured under the bonnet to reduce to speed of decent , to allow for someone to grab her before she his bottom and lays out of reach?? There is! :D got her back up back on and this time screwed securely to the transom of the dink and the for an hour...I worked like a Mad Man :x with WD 40 and had her running... sort of :x Next Trip into port ( my Brothers pier in Port Charlotte FL. )
I tore her down, cleaned everything ... really good... replaced Nothing but the plugs, made a number of adjustments and had her running better than she had when I had bought her a couple months earlier.
vizwhiz wrote:Something to mention - head bolts are usually considered "strain bolts" - they are made to stretch under load, and as such, can usually only be used once. Now I say "usually" because (a) when you're in a pinch you do what you have to do and things can often work just fine even though they aren't to "factory spec", and (b) I've replaced many head gaskets where I've re-used the head bolts and the motor ran just fine. (none were on outboards, however)

The reason I mentioned it is that outboards tend to be high power-to-weight ratio, lightly-built motors (not light-duty, built to weigh little) using alloys and such, and the head bolts and other fasteners and items like them can sometimes be more specially designed than an older cast-iron-block motor that uses regular off-the-shelf bolts and nuts.

I will defer to others on here who have rebuilt outboards and can attest to whether it is an issue, but the trouble can come when trying to get the head tightened back down evenly and with proper torque to make sure you don't blow a head gasket... :(

But I agree - you learn a TON of stuff (tonne?) from undertaking a project like that - even if you finally give up and throw it all in a box and haul it to the junk pile...it is definitely worth the effort if you are half-way inclined to try! Couple old tricks... (1) masking tape and marker - tag all the wires and hoses and even small covers and such with which end goes where, what it was connected to, up/down, or something that will help you get it back in the right way. Digital pics can be useful now if you'd prefer. (2) As much as possible, if you take a bolt/bolts out to remove a part, screw it/them back in the hole/holes and leave them where they belong...especially if there are different size bolts used on the same part (long bolts on one side, short bolts on the other, etc.) Sometimes, this by itself can help you figure out where something goes (that bolt is long, so the part must be bigger than this one I'm holding). :idea:

Have FUN, even if there are parts left over... :D

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Catigale
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Re: To rebuild or not to rebuild? What a F@&%ing question!

Post by Catigale » Tue Nov 02, 2010 12:20 pm

You have to be a real dumb a*** to drop your motor, don't you..?
:wink:


On loosening head bolts ..I think you want to heat the head, not the bolts, to free them up..

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