91 Mercury 115 Rebuild - Let's see how it goes!

[justchecking]

Re: 91 Mercury 115 Rebuild - Let's see how it goes!

Picked up my block today. It looks and measures perfect. The shop charged me $30 to hone 3 cylinders and $45 to bore and hone the bad one. Total with tax $79.86! See before/after pics of the bad cylinder. They ended up boring it to 3.390 in or 0.015 oversize because of some scratches. I measured many times with two different mics and inside gauges and they are all within the tolerance I can measure for taper and out of round.

I also cleaned up a few bolts today with a die. There are some specs on the cleaned up one because it's right out of the die. Is it possible to prevent corrosion when I reassemble?

Time to order parts!

 

[Chris1956]

Re: 91 Mercury 115 Rebuild - Let's see how it goes!

You can try the permetex aviation gasket maker to prevent or at least slow down corrosion.

 

[justchecking]

Re: 91 Mercury 115 Rebuild - Let's see how it goes!

Faztbullet I PM'ed you.

I haven't managed to do much on the block other than clean a few things. Waiting on parts.

I did pick up a nice dial caliper set with all the attachments and a full set of bushing/seal/bearing drivers for $30 total off Craigslist!

I also changed the timing belt and water pump on my Camry. The money I saved doing it myself will pay for all my motor parts. But I am SORE as heck.

Chris1956, I picked up the permetex, do I put a little on each bolt? Do I adjust the torque any?

 

[Faztbullet]

Re: 91 Mercury 115 Rebuild - Let's see how it goes!

Havent gotten the list on Email yet but yours is a small bore bottom guide piston engine.

 

[Chris1956]

Re: 91 Mercury 115 Rebuild - Let's see how it goes!

Use some permatex on each bolt threads. Torque values are the same.

 

[justchecking]

Re: 91 Mercury 115 Rebuild - Let's see how it goes!

Faztbullet, the powerhead was rebuilt or replaced in about 2009 I believe with top guided rods. Here's a picture of when I was cleaning parts.

Chris1956, I'll give that a try.

 

[MercMan82]

Re: 91 Mercury 115 Rebuild - Let's see how it goes!

Be careful if you have to measure close tolerances with those calipers. Most likely theyll prob be like +- a mile. The cheap ones flex too much to be accurate. Especially used ones. Do a proper calibration first thing.

 

[justchecking]

Re: 91 Mercury 115 Rebuild - Let's see how it goes!

I haven't gone away. I'm still collecting parts. All I've done in the last two weeks is flush and fill the power trim (that was some work, the manual doesn't tell you how to fill the system when you are starting on empty!). I also tried some aircraft paint stripper on the head cover. It took off the last coat of paint like right now, but didn't touch the original factory paint underneath. I guess that's better than nothing. When I repaint it won't look too bad and the paint will be more durable.

 

[iron1951]

Re: 91 Mercury 115 Rebuild - Let's see how it goes!

justchecking

what, if any manual, are you using for the 115 motor? I have downloaded the manual from http://1manual.com/Mercury manuals/Service Manual PDFs/TwoStroke/13645_2/cover.pdf and I have noticed section 4b Powerhead (4-Cylinder Engines) is missing and of course, that is the section I need. Would you have that section? If you are using a different manual what do you recommend?

Thanks

Anthony

 

[bryanwess2000]

Re: 91 Mercury 115 Rebuild - Let's see how it goes!

Was the machine shop able to clean up the integrated head on the bad cylinder. It looked like there was a good amount of piston transfer. If any of that stays on the head it will cause preignition and possibly ruin your rebuild. I wish someone nearby would have done my machine work for so cheap. I couldn't find anyone in Birmingham that would do a blind bore. Good luck with your rebuild. I know the prices for all the parts on a rebuild add up fast.

Also at the price they charged they probably didn't chamfer the ports or clean the block. Just be sure to do this. The manuals leave out a lot of need to know information.

 

[justchecking]

Re: 91 Mercury 115 Rebuild - Let's see how it goes!

Iron1951: I had the same problem so I bought a hard copy of the manual on line.

I PM'd you.

 

[justchecking]

Re: 91 Mercury 115 Rebuild - Let's see how it goes!

bryanwess2000: Yes they cleaned up the head, but there is a few small dents from where the rings hit. I'm going to double check though. I was wondering about chamfering the ports. I know they didn't do that. How do I go about that?

 

[bryanwess2000]

Re: 91 Mercury 115 Rebuild - Let's see how it goes!

Some say you can use a ball hone but I wasn't happy with the results so I bought a couple pencil grinders a straight and a right angle
one. They aren't cheap but I had to move my exhaust port timing about .030 because a ring caught the port so I needed them. It was recommended to me to chamfer the ports before honing to final size. I'm guessing because it's likely to throw a bur up in the bore and when its honed it'll knock it off. You can probably use some small files and sand paper. You just want to break the sharp edge to keep the ring from catching. After you chamfer it drag your fingernail across the bore to make sure you didn't form a ridge/bur inside the bore. Considering you have machine shops around you with cheap bill rates it would probably be fairly cheap to have it done. It's going to be tedious unless you have pencil grinders, even then you need small hands to work inside the bore.

 

[Jeep Man]

Re: 91 Mercury 115 Rebuild - Let's see how it goes!

Nice informative rebuild. As a source of information, you may want to check out another rebuild on the forum from 2 years ago. Steve Schefer rebuilt a Merc although he used a 135/150 block. Very detailed, descriptive post. Look up " The 2010 FrankenMerc Project".

 

[justchecking]

Re: 91 Mercury 115 Rebuild - Let's see how it goes!

Steve started his "The FrankenMerc 2010 Project" thread a short time after I bought the SeaRay with the bad 1991 Merc 115 and just a few months after I joined iBoats. I was originally going to just sell the 115, then I was going to sell it for parts, then I was INSPIRED to rebuild it after reading "The FrankenMerc 2010 Project"! I still refer to techniques in that thread, but the photobucket pictures seem to have expired. I was also recently PM'd by another beginner re-builder like myself with some questions and I referred him to that thread. Kudos to Steve Schefer. I've gotten some more great advice here as well from some other iBoats members such as Chris1956, brianwess2000, and faztbullet, and others.

Unfortunately my stingy company just informed us that due to this and that the rank and file aren't getting a bonus this year so I am waiting for my tax return to finish buying my parts. So I have been cleaning and tinkering the past two weeks. I'll also chamfer the ports tomorrow for something to do.

This is a fun project. I have some guys at work, a few of the neighbors, and my dad who just rebuilt a 1941 Case VC following my project...

 

[beatoangelo]

Re: 91 Mercury 115 Rebuild - Let's see how it goes!

Very impressive work! I have a pair of 2005 115 EFI engines with steering arms corroded to the point where the steering bracket bolt is coming out. Salt water operation! Your post with the engine lift and work bracket are outstanding.

 

[Yesterday]

Re: 91 Mercury 115 Rebuild - Let's see how it goes!

Agree with ^^beatoangelo, the lift/stand combo are simple and effective! Beacoup thumbs up! Good luck on the overall rebuild!

 

[mercurymang]

Re: 91 Mercury 115 Rebuild - Let's see how it goes!

That lift was nice. I wouldn't even post up a picture on the one i made now. :embarassed:

 

[Yesterday]

Re: 91 Mercury 115 Rebuild - Let's see how it goes!

LOL merc, same here!! Ancient worm drive hoist chained to the rafters, and a cordless drill with a socket on it to run it! Not nearly as pretty, but it does work.

 

[mercurymang]

Re: 91 Mercury 115 Rebuild - Let's see how it goes!

Wheels. Now there's a concept. Would be nice but mine was on soft dirt.