Estate sale lot of 18 - 25hp motors - Compression gauge variables.

[slowleak]

I went to an estate sale with no intention of buying anything in particular but ended up leaving with a truck load of older motors. All but a couple are 18hp models, 1958 through 1975 models.
After no one bothered to walk out in the garage in the cold, some old woman and myself were the only bidders who ventured out into the garage, the rest were more interested in the furniture and glassware I suppose. She made it clear that if I left the vintage decorations she'd leave me the tools and tackle, as in no competing bids.
The oldest is a 1958 Johnson FD12, then a 1959 Evinrude 18, a 1960 Evinrude 18, a 1961 FD15, a '62 Gale 15hp, a 1968 Evinrude Fastwin 18, a 1968 Johnson FD22A, a 1972 and a 1973 Johnson 25, an 1974 Evinrude 25, and one 1975 Johnson 25hp 25R75B.
So far I've had all but a few running, the FD13 has no spark and is dripping some oil from the prop seal, the Gale 15hp has no spark on one hole, and the '74 Evinrude is missing its fuel pump.
For a sale that was advertised as having outboards and fishing tackle, tools, and chainsaws, I was surprised to be the only one there for that stuff. There was more interest in the clothes in the closets and furniture than the garage or even the WW2 artwork on the wall in the hallway that didn't sell. I was only one of two men there, and the other guy never left the house likely not wanting to get his suit dirty.

 

[slowleak]

I started going through them all one at a time checking compression, they range from 96 to 105 psi with the Gale and the '58 FD 12 both having the lowest at 95/96 and 94/95 on both cylinders. The one that's different is the 1968 Evinrude 18, which is about impossible to pull, it gave me 199/200 on a compression test. It starts and runs but nearly rips my knuckles out trying to pull the rope. There's also a few boxes of parts and a few 58 to 60 parts motors in the mix too. The whole deal took all of that afternoon and the next day to haul away.

They all likely need basic maintenance, such as new water pumps, carb kits, and likely lower unit seals but they're all healthy motors. The one Johnson is a long shaft, I think its the 73 model, but the rest are all short shafts. All are the older 22ci block motors.
The gale is super clean, but looks like its been sitting for ages. it was hung up high in the rafters in a bag, ( a good many of them were hanging from the trusses above, two per truss, over the work bench in the front of the garage. The work bench was a full hardware store Pic-A-Nut assortment. There was also a few old steamer trunks full of other outboard parts as well many I've not ID'd yet. Plus about 40 good used teleflex cables, dozens of shift cables, controls, and other parts for larger motors.

Now, my big question is, what should I be seeing in compression from these things? With a range of 92 to 200 psi over the lot, but all of them seem to run just as well.

The one 25 with electric start and recoil start gives me different readings on the rope than on the starter. I get 90-91 on the rope, and 118/117 on the electric starter. '

I had a younger neighbor here crank a few over and he got 20 psi more out of most of them than I did so compression readings may be off depending on who pulls the rope or which gauge I use. I've got five gauges, the oldest, which came with the motors is a Sun brand model with a huge pistol grip and trigger for a release, the newest a motorcycle set from Snap On that has separate hoses for each thread size and length down to 10mm. Then I've got a Craftsman, likely from the 80's, a Matco, that looks just like the Craftsman but newer, a Foley/Belsaw gauge meant for small engines, and a Mac that is very similar to the Snap on.

Going engine to engine, with different gauges, I get readings all over the place.
On the 1958 FD12, I get 92 psi on the Sears and the Sun gauge but get 102/101 on the Snap on, 108/109 on the Mac, and 96 on the Matco.
If I jump to another motor, those that read higher on one suddenly read lower on the other. The Snap On, Matco, and Mac gauges are mine and have been treated well. The Snap On gauge is almost new.

I've never done a gauge to gauge comparison over this many motors, and am not sure if it means anything at all but the fact that one motor will read high on one gauge and low on the next, repeatedly, and do the very opposite on another motor is what I find odd but I suppose the fact that these are reed motors may have a lot to do with it. If they didn't run or at least fire up on fuel mix shot into the carb, I'd be more concerned but was wondering what the norm would be with these?
All of them feel quite strong when pulling the rope, the one that read 200psi is really hard to pull but not all that much worse then the lowest compression motor I tested.

 

[racerone]

Hard to believe you got 200 PSI on a 22 cubic inch motor.-----But on older OMC motors the recoil starter needs to be " timed " to reduce starting / pulling effort.

 

[cyclops222]

No bidding on the motors / tools.
People are scared of our new taxes on everything. Should be a ton of boats for sale this spring. All prices.

 

[slowleak]

New taxes on what?
We're talking $50 for the contents of a two car garage with a dozen motors and a crap load of tools and fishing tackle.
I paid less than $4 in sales tax. Plus I bought those who helped move it all pizza, about $75 back at my place, and a $27 30 pack of beer.
Any one piece of the whole lot is worth double what I've got in it.

There's been a lack of bidders at all the auctions lately, it started back in 2021 or so. There's plenty of interest in the furnishings, carpets, glassware, and kitchen wares but tools, boats, tackle, sporting goods, and collectibles has been without any competition for a while now.

If it were video games or cell phones the place would have been standing room only rather than 15 or so people in all.

The motor with the high compression reads the same on four different gauges, including one older Snap On gauge that was in the one tool box. Most of the others are around 90 to 110 or so. I took a piston depth measurement and its nearly identical to one with far less compression both at BDC and TDC. Its nearly impossible to pull the recoil, you have to wrap a rag around your hand, and get it up on a compression stroke and yank the cord super hard all at once. It fires right up though. I've got a '78 35hp that has crazy compression like that too, It always did, even when it was new.
Its nearly impossible to rope start and it eats a starter every year or two. One dealer told me to double up the head gasket but I never did.

5 or 6 years ago and that place would have been standing room only with prices going for more than new. Its not like there wasn't money being spent, the women inside were running the prices up like mad on stuff I'd have just thrown away. None of it was particularly old or valuable. There was plenty of bidding on the used cookware, the blender, toaster, etc.

 

[Mc Tool]

On the high compression one ..... I have seen 2/ motors with a small drilling , about 3mm, that goes from an area above the ex port on the cylinder wall to the roof of the port to act as a decompression port , others have a notch in the top of the port window, either way if it gets plugged with carbon it will be difficult pulling it over TDC.
200 psi is a lot . I would imagine youd need a fairly healthy octane rating to stop that melting pistons . .

 

[cyclops222]

Some Briggs and Stratton motors have a built in compression relief valve to ease a hand starter.

 

[jimmbo]

The 25s, have a different Cylinder Head from 18/20s, to make up for the Lower Piston Height in the 25. If someone stuck a 25hp head on an 18/20, then the Compression would be high enough to cause Detonation. But I doubt even that mismatch would have 200psi. Maybe with a very large Carbon Buildup in the Head and/or on the Piston...

 

[reelfishin]

I had a '67 or '68 model 18hp years ago that came on a boat I bought that was nearly impossible to pull, when we checked the compression it had 195 pounds of compression on each cylinder. The motor looked like new, the dealer told me that there was a bulletin about using two head gaskets on those to lower the compression. It helped but only brought the compression down to 168 on each cylinder. It stopped it from ripping the rope out of the handle but didn't do much for my knuckles when trying to start it.

I finally bought an electric start for it and just carried a battery but eventually gave up on it after finding a later 25hp that had factory electric start and a charging system but I put up with that 18hp for a good 10 or so years before finding it a new home. One you got it started it ran great, it was just that getting it going was painful. I don't recall it having any additional holes to relieve compression but can't say I looked for one either. I later found out that the original owner had sold the boat because he hated starting it so much.

 

[racerone]

There was never a decompression feature on the 22 cube models.----I find it hard to believe compression higher than 130 PSI on one.----Then again someone may have shaved the cylinder head looking for extra power.

 

[jimmbo]

I think the only engines that had the Decompression Feature were the 57 - 59 35hp, and the 60 - 61 40hp

 

[Mc Tool]

I think the only engines that had the Decompression Feature were the 57 - 59 35hp, and the 60 - 61 40hp

I was remembering a motorbike I recently resto'd , also remembering several older chainsaws with compression thru the roof , that req massive de-coke . My theory was that they were burning a lot of wood dust ( some old air cleaners didnt work worth a damn ) . Some of them you could see where the piston had hammered the dust/carbon into the head leaving no squish area .

 

[jimmbo]

A 2 Stroke Engine would not last very long if it were inhaling Wood Dust, and it wouldn't be Build Up in the Combustion Chamber that kills it

 

[Mc Tool]

A 2 Stroke Engine would not last very long if it were inhaling Wood Dust, and it wouldn't be Build Up in the Combustion Chamber that kills it

Your right jimmbo , it was all a big lie , your to smart for me , caught me out straight away .

 

[slowleak]

I tried to pull the head off the one with the crazy compression but it won't budge. I see 10 head bolts, and I removed 10 head bolts, and it won't budge, I've tapped, pounded, and twisted at it and it don't move. Not even a little.
Am I missing something here?
I was going to swap the head off another motor and see if that changed anything, or at least get a look at it.
(I tried five compression gauges, two Snap On, one Mac, one Matco, one Sears, and one ATD, all read between 194 and 200 psi on both cylinders.
I'm not the first one here, someone rewound the recoil with some bright orange high strength rope. The don't look like its been apart before though and the head gasket that's showing is pretty thick.
The whole power head is all original blue metallic paint, with some light paint loss from heat around the head and exhaust side but nothing alarming.

For what I paid for them all, I'm certainly not out much if its junk or hacked up in some way that makes it unusable. But it does run, its just nearly impossible to pull start. It needs one of those recoil handles off a snow blower and thick pair of gloves to make starting it easier.

 

[jimmbo]

Your right jimmbo , it was all a big lie , your to smart for me , caught me out straight away .

The Bearings would be gummed up real quick

 

[Mc Tool]

The Bearings would be gummed up real quick

Yep , inlet tract , crankcase and transfer port runners were all dusted with saw dust that got past the disintegrating felt air cleaner pad thing ). I dunno just how long it took but the cust said it had got harder and harder to start. We got it when the recoil starter gave up

 

[jimmbo]

Felt Air Cleaner? For the past 50 years I have seen nothing but Foam Filters on Chain Saws, so that one you are referring to, must be really old

 

[Mc Tool]

Felt Air Cleaner? For the past 50 years I have seen nothing but Foam Filters on Chain Saws, so that one you are referring to, must be really old

Know what jimmbo , I cant be bothered with you , nit picking p.i.t.a , basically ( in not so many words ) calling me a liar and now your just taking issue with anything I post .
lets see what you can do with this aye jimmbo ..........yes it was an old Remmington or Homelite saw when this happened in the early 1980's ,

 

[jimmbo]

Know what jimmbo , I cant be bothered with you , nit picking p.i.t.a , basically ( in not so many words ) calling me a liar and now your just taking issue with anything I post .
lets see what you can do with this aye jimmbo ..........yes it was an old Remmington or Homelite saw when this happened in the early 1980's ,

Early 80 Saws, to me are practically Brand New. When you said Old, I figured you meant something pre 1950