175hp cylinder walls and absurd compression results

pastorbud

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Jun 1, 2005
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Guys with more experience than me tell the compression readings I’ve been getting can’t be right: 60 psi on two cylinders, with the others showing 60 psi while cranking, but dropping to zero when I stop cranking.

Word is that’s a bad gauge or I’m not using it right. But I got the same results with two different gauges. And it got 60 and held on some, but went to 60 and dropped on others. I was using the same gauges the same way each time. I’ve run compression tests lots of times on multiple engines. They’re kinyda hard to mess up. What could I be doing wrong?

I pulled the heads and took pictures, which I’ll post below.
 

racerone

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It has been clearly stated that a compression gauge only goes to zero when you push the release valve on the gauge.----They do NOT go to zero any other way.
 

pastorbud

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I wish I’d shot a video. All I can say is I watched it happen. I didn’t press the release valve, I just released the jumper switch that I was using to crank the motor. Time after time, two different gauges. I’m probably doing something wrong, but whatever it is, I didn’t press the release valve.

Uploading photos now.
 

pastorbud

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Starboard lower
 

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pastorbud

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Starboard center
 

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pastorbud

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Well, I lost track of my labels, so I’ll have to re-shoot, or I won’t be able to tell them apart. Not my best work! :(
 

Faztbullet

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The hole with the Siezco piston is worn out. Looks like it scuffed at one time and someone honed the crap out of it and slapped a new slug in der hole.
 

pastorbud

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The hole with the Siezco piston is worn out. Looks like it scuffed at one time and someone honed the crap out of it and slapped a new slug in der hole.

So I’m looking at a rebuild, right? No way to repair just that one cylinder?
 

racerone

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Decisions are based on FACTS.-------I would run to a machine shop and MEASURE the cylinders with some degree of accuracy.----Then decide what needs to be done.----Post the numbers here.
 

pastorbud

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Decisions are based on FACTS.-------I would run to a machine shop and MEASURE the cylinders with some degree of accuracy.----Then decide what needs to be done.----Post the numbers here.

Since it looks like I struggled to use a compression tester, I may be an unlikely candidate to get accurate cylinder measurements without outside intervention.

But I do have two ASE certified mechanics in the church where I serve. I’ll get their help and post the measurements, Lord willing.

Might take a while. Snow coming soon!
 

Cdwill0108

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MOD EDIT - A bit presumptuous to come from a 2 hour member.
 
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havoc_squad

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Help me understand what that means.

I wouldn't be suprised if it was one of those "Hold My Beer, I'll Fix it" :facepalm: moments from someone with no proven skills posting some recommendation with no evidence.

If it wasn't, I'm sure experienced ones here have seen that happen a few times.
 

pastorbud

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Decisions are based on FACTS.-------I would run to a machine shop and MEASURE the cylinders with some degree of accuracy.----Then decide what needs to be done.----Post the numbers here.

So I have photos and measurements on one cylinder... I thought it best to post each cylinder as I go. It's like 20 degrees out today, and I have to come in and warm up periodically anyway. Plus I want to make sure I'm doing it right.

I don't have a connection at a local machine shop.. just an outboard repair shop. They'd probably just inspect and give a quote to rebuild/repair. Not much support for us DIY guys.

I did get a telescoping tool and a caliper, watched a couple of youtube videos, and talked to three pro mechanic friends. (Two Fords and a small engine guy.)

I tested the caliper by measuring a couple spark plug feeler gauges to be sure, for example, that the
.004 inch

feeler gauge actually tested as .004 inch with the caliper.

I measured one cylinder at the top and bottom of the stroke (the area on the cylinder wall where the rings contact), in four different dimensions (or axes): 12 and 6, 3 and 9, 10 and 4, and 2 and 8 o'clock.

And I took each measurement twice.

Model E175TRXCNB
Portside top cylinder (is that called Cylinder One?)

Bottom of the stroke

at 12 and 6 o'clock- 3.498, 3.497
at 3 and 9 o'clock- 3.498, 3.498
at 10 and 4 o'clock- 3.496, 3.497
at 2 and 8 o' clock:- 3.497, 3.497


Top of the stroke
at 12 and 6 o'clock- 3.497, 3.496
at 3 and 9 o'clock- 3.497, 3.498
at 10 and 4 o'clock- 3.498, 3.498
at 2 and 8 o' clock- 3.498, 3.497



Here are the pictures of that cylinder at four different orientations. There are remarks included on each one.

I cleaned up the cylinder walls with a brass wire brush and PB blaster. There are marks and discoloration, but nothing I can feel anywhere with my finger, or scratch off with my thumbnail.

Please lemme know if there's anything I need to do differently to measure the remaining cylinders.
 

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