Powerhead rebuild

[Pony]

I've posted about my 71' 60hp evinrude triumph a few times. I finally got it almost complete and running the way i wanted, with the exception of link n synching the carbs and adjusting my idle mix. Well it turns out that when when water pump failed a week or so ago, i did a lot more damage than i thought. Im not sure, but i thought this motor had a mechanism to shut it down when the pump fails to avoid overheating, at least thats what i believe happened last time the pump went. I replaced the water pump and impeller, but the engine wouldnt idle. i checked compression....my best cylinder's compression was 86 and the worst was in the 50's or 60's. At any rate compression is bad enough to not idle. So obviously i need new pistons and cylinder need to be bored bigger. Problem is the wrench told me it would be about $1,700 to rebuilt the powerhead. I love this boat and i love this motor, and ill do anything to get it running again. Money is the issue right now. Im thinking about trying to do the work myself. It would be a learning expierience and i guess that even if i mess it up, its not running anyways....I have a few questions about this though.<br />1. Is this a job that i could even possibly do myself. I've never done anything like this before. ( i have a seloc repair manual for it).<br />2. If i do attempt this myself what special tools will i need to do it correctly.<br />3. Will it be worth it?<br />4. Is there anything i can do to avoid this happening again if i ever get the engine running again?

 

[Hotrods]

Re: Powerhead rebuild

Yes<br />Yes<br />YEs<br />Yes.... <br /><br />Im in the process. Read Sticky rings <br /> "sticky rings" <br /><br />and most of your questions will be answered. with more to come..<br /><br />Rod

 

[Pony]

Re: Powerhead rebuild

One other question i have is about honing the cylinders...Im having a friend of my dads, who is a machinist, hone the cylinders. What is the best procedure. Is it better to buy the oversized pistons and have him hone the cylinders to specs or buy pistons according to his bore measurements? Sorry if this seems like a silly question. As i mentioned above i have no epirience in repairs that are this involved.

 

[R.Johnson]

Re: Powerhead rebuild

If the cylinders are within specs. They can be simply hones, but I doubt that that would be the case with a 71 engine. More than likely you will need to have the cylinders bored oversize. For this, you will need to find a shop that is familiar with 2 cycle engines. Once a shop is found, they can advise what step's are needed.

 

[NEECAPRS]

Re: Powerhead rebuild

Pony: Notice the subtle message from R. Johnson: The cylinders probably need to be BORED. Honing a two stroke oversized is really tough. A very rigid hone is the only way anyone could do it with straight, round results.

 

[Pony]

Re: Powerhead rebuild

Im guessing that i would be better off going to a marine mechanic to do the honing/boreing then. This is believe it or not going to be the first time that the cylinders will be touched at all in the motors 33 years of age. Does anyone have an estimate as to how much something like that costs?

 

[Hotrods]

Re: Powerhead rebuild

I paid 40$ for block cleaning and 40$ a hole @ 20 over. And from what I understand the tolerences are higher on the 2 stroke. more clearence. so the shop will need to know the 20 over piston size, then the size the bore needs to be. My shop hit it right on the nose.. nice fit..

 

[Pony]

Re: Powerhead rebuild

Thanks Rod....That doesnt seem too bad at all. I just hope i will be able to find all the gaskets i will need.

 

[Hotrods]

Re: Powerhead rebuild

Thats no problem. you will get a full gasket kit. If I can do it anyone can. what I have learned from these guys I will for sure pass it on...along with the "what not to do" I have a nice list of them....lol<br /><br />OH and My marine supply said it was no good for me to bore anything over that omc doesn't carry. i went 20 over and bought "after market pistons". he said they are NG.. well BS to that. I got Weiscos 20 over for 80$ a piece.<br />And everone fit like it needed to

 

[Pony]

Re: Powerhead rebuild

Well im doing lots of soul searching. It seems like i can get the parts (hopefully), and i have two manuals (seloc and clymer). The thing that bothers me is that i keep being told "you have to know when its time to cut your losses". I've worked on the interior of the boat for 2 summers now and am just reupolstering the seats and adding a bilge pump and new gas tank away from finishing. This year i worked on the trailer(new bearings, wires, lights, tires,rims, rollers, paint....you name it i did it.). I had finally gotten around to the engine (rebuilt carbs, fuel pump, and all new fuel lines), then the water pump and impeller (after pump blew and overheated engine to current state). Now its hard to turn back after that much work...to everyone that tells me to cut my losses i've said that even though its a 71' it will be like new and i cant even imagin the personal pride i will feel if i do it by myself. The question is should i risk it, should i spend mony on repairing this engine? I guess what i am asking is how hard is it really with the motor being as old as it is, and being that old, is it still worth it? just curious as to you guys' thoughts on the matter. any input is appreciated.<br /><br />P.S. hotrod...If i do attempt this i hope it turns out half as good as yours...looks incredible.

 

[misterbluesky]

Re: Powerhead rebuild

Consider looking @ this site pony85. www.tenkillermarine.com/boatsparts . I also just discovered Bad #2 piston on a 93 60hp evinrude that I might do myself. Add up cost of parts, gaskets, machining, & your time. And hope you get everything right (whats your warranty to you?) I like you don't want to give up my motor or boat & am considering my own rebuild. Check out this site & let me know what you decide. Good Luck!

 

[Dhadley]

Re: Powerhead rebuild

Before you spend any money, locate your pistons first. Neither Wiseco nor Vertex make pistons for that motor. An Evin/John dealer can see if they're still available thru BRP. <br /><br />If not we may have to try some places that specialize in older parts.<br /><br />Good luck!<br /><br />BTW -- be leary of a machine shop that says they have to measure the piston before they bore. There are shops that can do it accurately but some cant. Todays pistons are tapered, cam ground adn sometimes barrel shaped. Really tough to measure.

 

[Pony]

Re: Powerhead rebuild

thanks...good point dhadley. I also better make sure i locate all my gaskets.

 

[walleyehed]

Re: Powerhead rebuild

Thanks DH for adding the "gotta have the piston to make it work" as being an indication of a worthless shop, Or, at least in my opinion it is...<br />People need to understand ALL measurements are from std bore of the BLOCK...hence .020 over is .020 over std bore of the block, the piston may not be .020 over a std piston.

 

[Pony]

Re: Powerhead rebuild

After searching for pistons, i see that 1980 seems to be the earliest year i can get them from. Im still trying to look around for parts. Hopefully i can find this somewhere. I find it hard to believe that parts aren't available for these things since there seems to be quite a few still around. How different are these pistons, is it remotely posiible to use pistons that are just similar enough? I know sounds like a stupid idea, but im reaching for anything at this point

 

[Dhadley]

Re: Powerhead rebuild

OK heres something you might try. Be interesting to see if it works. A Wiseco 3115 series piston fits back to 1972 if you use the wrist pin bearing kit B1029. <br /><br />Your 71 has a very slight hump on the dome. The 72 and newer is flat. I'm pretty sure the standard bore is still 3.00". If so, great so far.<br /><br />You might order a 3115 in whatever oversize you need and compare the pistons. As long as the distance from the wrist pin to the top and bottom are the same it might work. You may loose a tiny bit of compression.<br /><br />If there's something totally different about the piston you can just return it.

 

[Pony]

Re: Powerhead rebuild

I searched for some parts at twincity.com yesterday and recieved a response along the lines of " pistons are only available from the dealer...the amount this will total to properly rebuild will be a good start to paying for a much better, newer motor" <br /><br />So, to say the least that doesnt make me feel good about this. Maybe im being stubborn but im not sure that i find that last statement to be true yet. The reality is if im going to buy a new motor, i pretty much need the boat also because if im going to spend that much i almost have to go all the way. I mostly use the boat for fishing, and a tri-hull isnt really designed too well for it....<br /><br />Again im at a loss...im really pondering that piston idea dhadley. I guess i figure that losing a few pounds of compreesion is alright as long as the compression is even, right?? Is the bump on the piston that important considerong the internals are very close between the engines. Will it affect the way the engine runs, the bump must have a purpose right??<br /><br />Sorry for the long post...lots on the mind.

 

[BF]

Re: Powerhead rebuild

Are there any decent used OB's for sale where you are? You might come out having spent less $$ by buying a complete used motor, even if you put a few dollars into it, and then parting your old one out. I'd think the lower unit should be worth a few bucks. Of course, the down side is that you wouldn't have a newly rebuilt motor on your boat.<br /><br />In these parts, older outboards of the 70-80's vintage don't fetch much for re-sale, even though with our short season they often don't have very many hours use on 'em. Usually more neglected than worn out. Fairly common to see 70-80 hp ones listed in good cond with controls for < $2000 canadian, often much less.<br /><br />Or maybe you could get ridiculously lucky and find another '71 60 hp with a good powerhead but wrecked lower unit for cheap. Then you'd just need to stick your lower unit on it and you'd be golden.<br /><br />Anyway, that's a few thoughts on options other than rebuilding.<br /><br />Good luck.<br /><br />Brent

 

[Pony]

Re: Powerhead rebuild

The current plans are to still rebuild the motor....I talked with i guy i currently work with who worked at Evinrude during the time that this engine was built. We've had several talks, and he seems to think that dhadley's suggestion will work...or at least he cannot think of any reason why it wouldn't. Do I assume that i will need new needle bearings etc. with this rebuild?? And as far as gaskets go, does anyone know if they still make those at least? what other sorts of tools, sealants, and things of that nature will i need. I am already looking at some torque wrenches....<br /><br />BF, I had been looking at first in the paper etc for a used OB, but the more i think about it, the more i want the epirience of doing this rebuild. This mtor has intrigued me since i was a little kid when my dad had it, and now i may get a chance to know it inside out.<br /><br />Any suggestions as to where to look for gaskets (dealer, internet) and what thisng i may need to do this properly would be greatly appreciated...Thanks in advance.