guess I gotta take the head off again

[sprouticus]

I took the head off my boat recently, had to have a helicoil installed. While it was off I cleaned up the carbon that was on the piston, and checked the cylinder wall for damage (didn't find any). I wiped down the cylinder wall with an oiled rag, put everything back togeather, and took her out for a run. She ran pretty good..............that was last week. Yesterday I had it out for the day and it died, leaving me stranded in the lake.<br /><br />Some background information........I have a 1977 70 hp evinrude. I use 2, 20 litre gas tanks. When the motor died it was just after we ran out of gas on the first tank. I was in the tube at the time so my buddy switched tanks and went to start her up again. She turned over and started briefly, and then died again........and when he went to turn it over again, it wouldn't. I came in and hooked up the electronics battery to help jump the motor battery.......the motor still wouldn't trun over. So I wrapped a rope around the flywheel, and figured I would turn it over that way (I've had to do it before.this is why I have a extra battery for the electronics ) Anyway the flywheel would not budge. I tried to turn it by hand, and could hardly move it. It was in neutral, it should have been fairly easy, but I could barely move it. Oh, and the gas was mixed properly, and the motor was not too hot when this happened (I could feel heat, but could leave my hand on there forever). I am about to pull the head again and check for scaring. Any suggestions guys???? I am assuming I am in for a lenghtly rebuild that I cannot afford..............sigh ..........sucks to be me.

 

[OBJ]

Re: guess I gotta take the head off again

Yep...anytime you have to rebuild....it does suck.<br /><br />One thing that comes to mind, are you sure the engine didn't cold seize? Was the engine running at normal temp?<br /><br />Have you tried to turn the flywheel since it quit? You can get lucky sometimes and no damage is done if the engine did seize.<br /><br />If you can turn the flywheel, then get some compression readings.

 

[sprouticus]

Re: guess I gotta take the head off again

I have never heard of a cold seize before..what does it mean, and how did it happen???? I just went out, and tried to turn it over by hand, it was still difficult, I hooked it up to the muffs, crossed my fingers, and amazingly, it started. I think it sounded a little weird, so I shutted it down. ran a compression check.........was 90, 118, 118. 2 weeks ago before I took the head off it was 120, 118, 118 and after I put it back on it was 114, 118, 118. SO I have lost serious compression on the top cylinder.<br /><br />I wanted to recheck the top again to make sure, but it wouldn't turn over, even while boosting the battery. And 2 weeks ago it was easy to turn the flywheel by hand, yesterday it was difficult, now it is impossible. I want to pull the head, and take a look, but first I need someone's advice. <br /><br />My marina does not carry head gaskets for my boat, they take like a week to come in. I put on a new one last week when I pulled the head, so...........is there a chance I could reuse the same head gasket???? I am guessing not, but am hoping someone will tell me I should be OK. Otherwise I have to take a week to work on it.<br /><br />thanx for reading

 

[sprouticus]

Re: guess I gotta take the head off again

ok..........head is off, and my worse fears have materialized. The head is scared, the piston is pitted, there were small pieces of metal imbedded in the head. the cylinder walls don't look too bad, I can just barely feel a minor scratch when i rub my fingers around it. <br /><br />When I dug out the small pieces of metal, they were about 1.5 millimetres accros. I have no idea where these came from. <br /><br />There are some holes in the cylinder about 1 inch by 1 inch. I think the are exhast ports, not sure what else they could be for. I can see metal has collected in these holes. They are not loose, but more like they have been compressed right next to where the piston had been rubbing them. I am assuming that somehow this metal came in through these ports, but I still have no idea what they are or where they came from. <br /><br />Do I have to buy a new head guys????? or can the old one be sanded down???? I am pretty sure I need a new piston, but do I need to re-bore the cylinder wall???? Any guesses on where the metal came from???? oh, and I think I can use the head gasket again.its about the only piece I saw there that wasn't damaged. sigh...........<br /><br />well thanx for reading

 

[OBJ]

Re: guess I gotta take the head off again

The metal bits you see are probably pieces of the rings. How bad is the head pitted? If they are not to bad, a dremel tool can be used to smooth them out. What you don't want to do is leave places for carbon to form in chunks. They can glow and cause pre-ignition.<br /><br />A cold siezure happens when the cylinder can't expand with the pistion because the cold water is around the cylinder prevents the cylinder from getting warm. Not as common as overheat siezure, but can happen none the less.

 

[sprouticus]

Re: guess I gotta take the head off again

if a cold seizure is what happened....what can I do to prevent it in the future???????

 

[Solittle]

Re: guess I gotta take the head off again

You won't be able to tell the extent of the damage until you get it apart and have a shop inspect and measure the cylinder bores. My guess is that at a minimum you are looking at getting that cylinder bored, one new piston, a set of rings and a gasket set.<br /><br />The most important thing is to determine the cause of failure or it is likely to happen again.<br /><br />Oh and it is best not to reuse the head gasket.

 

[sprouticus]

Re: guess I gotta take the head off again

so if that is the case.............any guesses on approximitly how much money I am looking at to get a shop to rebuild??????? (please specify wether canadian or american dollars) <br /><br />I think I have to take the fly wheel off to get the piston out (pretty unfamilar with outboards) I rebuilt my dirtbike a few years back.........but it was one cylinder and no flywheel. I have never taken a flywheel off.....but from what I read it sounds pretty hard. So I better get the shop to do it. <br /><br />thanx for the help so far

 

[duck64]

Re: guess I gotta take the head off again

Letting it run out of gas at high rpm's is not good for the cylinder walls

 

[sprouticus]

Re: guess I gotta take the head off again

thanx for that tip.................this is my first year with a boat and nobody else I know has one, so iboats is my only source for information.

 

[Cricket Too]

Re: guess I gotta take the head off again

sprouticus...Is that what happened, did the motor run out of gas when you were cruising at high RPM? If so then that is the cause of your problem, top carb went real lean and burnt up that piston.

 

[sprouticus]

Re: guess I gotta take the head off again

thats what happened.........but thats what I always did.....I use 2 remote tanks and I just run them till I run out of gas and then change tanks.........nobody told me to do otherwise. I guess it makes sense...no gas=no lube in the cylinder. I feel like a dumba$$ now. Sigh...is there anything else I should know guys............this stupid mistake is going to cost me a few bucks

 

[joblo33]

Re: guess I gotta take the head off again

Where are you in BC sprouticus?

 

[sprouticus]

Re: guess I gotta take the head off again

Penticton..about 45 mins south of Kelowna. Hey, hows the Salmon fishing on the island????

 

[Solittle]

Re: guess I gotta take the head off again

Working on these engines is not rocket science and can be kinda fun if you have the time and a decent work space. If you decide to play with it yourself make sure that you buy the OMC shop manual specific to your engine. It has detailed procedured, diagrams and pictures.<br /><br />You will have to completely dissassemble your engine, take it to a marine machine shop for the precision work, get a gasket set and put it back together.

 

[sprouticus]

Re: guess I gotta take the head off again

well I got a quote on getting a shop to rebuild it for me...............$1200. so I called another....$2000.........guess I am not getting a shop to rebuild it. I found my motor on e-bay about a month ago that went for $1200..at the time I thought that was a crazy amount..now I'm thinking I wish I bid on it. <br /><br />Anyway I placed a bid on a shop manual for my motor. I will try to do the work myself I guess. Can I bore out just one cylinder?????? the guy at the shop said I couldn't but someone on hear said I could. The only part that is scaring me about this new project is pulling the flywheel and putting it back on. <br /><br />well.i'll let you know my progress, but first I have to wait for the manual to come in.<br /><br />thanx for reading

 

[DHPMARINE]

Re: guess I gotta take the head off again

Flywheel Pulling 101<br /><br />Remove nut.<br /><br />Attach 3 bolt puller,turn center screw.<br /><br />POP ! !<br /><br />To put it back on,just align the keyway,and let it set down.Install nut and torque to spec.<br /><br />DHP

 

[janker]

Re: guess I gotta take the head off again

If you have the time, this isn't TOO bad of a job to do--if you've read my other post, you'll see that I've done it myself a number of times!<br /><br />You CAN bore out one cyl only--but find a good shop and have them examine the block once you get it apart. If you're lucky, the scores can be honed out and you won't have to actually have the block bored out. Here's another piece of good news (relatively speaking) If the scoring is TOO bad (On my Evinrude you can go 30 over; I don't know about your model) a qualified shop can drop in a sleeve and bring it back to original specs.<br /><br />Like I said, if you have the time, this can be a fun learning experience, and you'll save a TON of $$ on the rebuild.<br /><br />One more question: Was that quote for the rebuild in Canadian or US dollars?

 

[sprouticus]

Re: guess I gotta take the head off again

The quote was in Canadian dollars. Its funny cause a month ago when I saw the EXACT same motor as mine going on e-bay for $1200 plus shipping. I thought that was a rip-off at the time........now I wish I had bought it for parts if nothing else (the ad said it was in perfect shape) <br /><br />The scratches on the cyl. wall are very minor I think, hardly noticable, and compresion was still 90 on that cyl. before I took it apart (but it used to be 120)<br /><br />and John Anker........in case no-one has told you this yet......welcome to i-boats <br /><br />DHP........thanx for your help, I think I have to go do a search now on what a 3 bolt puller is

 

[BoatBuoy]

Re: guess I gotta take the head off again

SJDiscountTools.com Puller, $12.97:<br />