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Irwin 32.5 Ketch
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3 Posts
Discussion Starter · #1 ·
Ever hear of a Perkins 4-108? Sure you have, but how about his older, annoying self-entitled brother, the Perkins 4-107? It's like getting stuck with Payton Manning on your fantasy team, because you lost Eli in the first round. There are advantages to both, but I always thought age was the number one factor when it comes to performance... most of the time.

We'll that's what I got stuck with in my tub, the 4-107, so I'm going to try to make the most of it. I've learned a lot about this little guy. He actually has an attitude, so i'm going to try to make him happy this season with some upgrades that will take that pit out of my stomach every time I leave the dock.

This is a record of my winter project, working on the engine.
 

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Irwin 32.5 Ketch
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3 Posts
Discussion Starter · #2 ·
WTF am I Doing Here?

It’s winter 2014 in Connecticut and I’m on my 1972 Irwin 32.5 Ketch. It’s cold, but I only have a few months to get ready for my third season with the boat.

Let’s start with the issues I’m having:

Rear Oil Seal:

Since day 1 I’ve had a slow oil leak near the rear of the engine. Easy enough, just drop a pan or bilge pad under it and change it out every few weeks. The leak started to get worse over time and then it became an actual issue. Motoring for just a few hours would dump at least a quart in the bildge. I got tired of shop vacuuming and scrubbing every time I came back from a trip.

Leaky Exhaust:

You know that burning in your nose and eyes every time you run into the galley for another drink? Well I realized that’s not normal and the 40 year exhaust system needs some changes. Mostly hoses, so we’ll save that for last.

RUST:

Like a fungus, this stuff continues to spread. It didn’t even look that bad three years ago, now it’s EVERYWHERE! So as I’m removing parts, I’ll be inspecting cleaning and repainting as needed.

PARTS:

As most of you may already have noticed… the engine is over 40 years ago and from what I hear, they stopped making parts for the 107 back in the 80’s (not actual fact). So I’ve spent most of my time online and have identified a few places that have 4-107 parts.

Fuel System:

Nothing better than leaving the marina and having your engine die right as you’re navigating the mooring field. Air in the system, fuel cut off, whatever has been a problem for a while. I’m hoping it’s the lift pump, which I actually did find a replacement for. If not it’s the fuel pump and I’m not going to touch it until last, if needed.

Leaks:

And there are a number of random leaks around the engine that I’m hoping will be addressed when I replace the gaskets.

OBJECTIVES:

I’m going to address all of these issue in the next few months. Basically do an in boat overhaul without touching anything inside the block so I don’t mess up the engine timing.
 

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Learning the HARD way...
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7,835 Posts

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Mechsmith
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240 Posts
I feel like talkin. Hope you feel like readin.

First when you have an older motor lets see what you have as far as the hard parts are concerned.:(

Get the thing warmed up and take her out some. Then pull the oil filler cap and watch it. Bring it up to full load. There should be very little smoke and vapor coming out of there. If there is a lot coming out of there you have just determined that all the gaskets and seals won't help. That is good to know. There are cheap PCV testers at auto parts stores to give you a further clue. Any pressure from the combustion chamber that gets into the crancase is not good. Actually it's bad. A stuck or broken ring will let the fire down past the piston. There are a whole bunch of scenarios from there on. (none good) IF OK then---->

See if your compression is even. Take a piece of chalk (motor still warm) and mark your crankshaft pulley where the marks from the factory probably are. Then chalk 180degrees from that. Turn your motor over (with a ratchet wrench if necessary). Don't break the bolt off. As you turn the motor over as each mark approaches they should feel the same. Turn the motor at least twice on each mark. If you run into one that turns past the mark much more easily than the other ones you have a compression problem. If you have a compression problem don't bother with new gaskets etc!

If for some reason the main bearings are a bit loose the rear main seal will soon leak again. You can check this by putting the crankshaft 90deg off one of the marks and then moving the flywheel up and down. A dial indicater is nice to have and if you have one you can figure out how to use it. The flywheel should not move vertically more than .0025" That is 2 and1/2 thousands. The bearing wear in that type motor is mostly vertical. If you can see any difference pushing the flywheel from side to side as opposed to up and down you have a hard problem.:(

You can use an electric lift pump. About $40. If you need some more talk let me know.:)
You can fool around a long time with gaskets and seals without fixing very much if a hard part is worn out. (Rings,pistons,bearings,valves, sleeves etc.)
 

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Learning the HARD way...
Joined
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7,835 Posts
I feel like talkin. Hope you feel like readin.

First when you have an older motor lets see what you have as far as the hard parts are concerned.:(
Great post - that earned you a rep point. That and $3 buys you a coffee at Starbucks.:)
 
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