There's a question at the end, but mostly I'm posting this so that others can see how one of these motors is brought back to life. I dug up a lot of useful info from the archives of these forums, and this story could be useful for someone wondering where to start.
This started out with my cousin giving me a nice 1989 20 hp Johnyrude my uncle had.(yes this is an Eska story, I'll get there)
So I was looking for a suitable boat to run it with, and found a 14' Crestliner. It had a non-running 3.5hp Eska (Sears Gamefisher) hung on the back. Didn't really want the dead motor, but the PO threatened to charge me extra if I didn't take it. "About three years ago, It just quit and wouldn't start and I had to row in. Don't know what's wrong with it..maybe you could fix it, I'm not mechanical".
So I pulled it off and started fixing up the boat (The plywood seats were rotted out)....but then I got to looking at that sad little Eska girl, and wondering what she needed to make her happy? Kind of like how I can't resist a puppy....
Giving her a few pulls showed the compression was good, but no signs of life. Pulled the (origional, with paint) plug, and it was in good shape and there was spark. A teaspoon of premix in the carby, and the little girl showed signs of life. OK, might be kinda fun to see if I can bring this thing back from "written-off and I'll pay you to take it."
Broke the paint seal on the carb nuts, and found the nastiest mess I have ever encountered in a carb. It was a dry brownish foamy stuff everywhere. No gas would flow through the inlet fitting even...couldn't even get a bicycle spoke through, had to use a drill bit.
Cleaning the bowl revealed the holes eaten through the bottom where nobody had EVER dumped water out. Broke the carb down and soaked it in the canned cleaner. It cut the muck, and also took most of the paint off...didn't seem to hurt anything vital though.
So it turns out we have a dead lawn mower with a Tecumseh I haven't got around to taking to the dump yet, and I recalled that I had put a new float and needle on it not too long before we replaced it, and danged if they and the carb bowl weren't the same as this boat motor has! Put the clean carb back togethor with the seat, needle, float, and bowl from the old lawnmower.
I managed to tear the pump element taking it out (the brown goo was holding it in pretty tight) and the valve membrane and gasket weren't too great, so I ordered those from an online vendor. Set everthing up per a Tecumseh carb manual I found online.
She hit on the first pull with full choke, and on the next pull with half choke she was running and smoothed right out as she warmed up. Seemed to have lots of power(near as you can tell running in a barrel) but wouldn't really idle down. The idle needle didn't seem to matter where it was set within the range of the stop plate. Really didn't want to run slow enough to troll with, and would even be fussy coming up to a dock...especially since this is a fixed gear (no neutral, spin it for reverse) motor.
I didn't have a new 7/16" Welch plug for the idle circuit area when I cleaned the carb, so I had just done the best I could with spray carb cleaner. The spray tube that comes with the carb cleaner fits into the idle air intake real nice, as does the tube for the canned air to dry it out with. Managed to get carb spray coming out all the holes (fuel pickup, air intake, needle hole, two transition ports) though....but I figured there was still some muck in there blocking the idle circuit.
The guy at the lawnmower and chainsaw shop didn't have a plug by itself, but he had a kit with the plug and some gaskets I should have replaced anyway for ~ $5.
I pried the Welch plug out and found the idle circuit was pristine....gave it a scrubbing anyway, and made sure I could see daylight through the little transition ports. Installed the new Welch plug, and sealed it with some of Susan's nail polish. (Now I just need to come up with a good story for the greasy thumb print on the bottle!)
Still no idle. When it died slow, it wouldn't restart without a prime (Either a squirt of gas or a pull with choke) so I figured it must be lean at the low end.
I had put the idle needle stop plate back where I found it....about 3/4 turn out. The guy at the small engine place said most Tecumsehs liked about 1-1/2 turns. So I moved the stop plate some, and at ~1-3/4 or 2 turns was able to get it to run down almost slow enough to count the revs...shakes a lot running that slow, but otherwise happy. Good transition to mid throttle too. Now adjusting the low speed needle makes a difference...yeah!
Ahh, but for every silver lining there must be a cloud: now it 4 cycles above about half throttle. Runs better when cold than hot, and gets worse if I hold my finger in front of the intake, so it must be rich...did I mention I live at almost 5000' altitude?
So I'm thinking somebody in the past had set the idle needle down to almost closed to compensate for over-rich main jetting. Now that I have the idle circuit set where it belongs, she's getting way too much gas when the main jet comes on line.
This carb has a non-adjustable main jet. It is the sort with the jet as part of the bowl nut. It is stamped 39, but this doesn't fit with anything in the tecumseh carb manual, though it does talk about this carb as a "type 2".
The carb kit I bought to get the Welch plug came with an adjustable main jet, and low speed needle, but but they don't fit this carb.
I have made jets in the past...lived my whole life at altitude, but this one is more brass than I want to buy, and more complex than I want to spend time on the lathe.
So my plan is to measure the jet with pin guages, then solder a wire in the existing jet and drill a new hole with about 20% less cross section area (based on experience with motorcycles at this altitude). Yes, I have some microdrills, and a dremel press to spin them fast enough not to break. If it doesn't work, I can solder up the new hole and go back to the old one.
Anybody see a problem with this plan, or know where I can find info and parts (hopefully cheap, 'cause I'm that way*) to "do it right" as far as re-jetting?
*A can of carb spray, Carb dip, carb parts, and a chunk of fuel line, and I'm up to about $35-40 into this motor, and we all know that is a big chunk of what they are worth. Does my heart good to bring a machine back from the dead, but have to be reasonable about it.
This started out with my cousin giving me a nice 1989 20 hp Johnyrude my uncle had.(yes this is an Eska story, I'll get there)
So I was looking for a suitable boat to run it with, and found a 14' Crestliner. It had a non-running 3.5hp Eska (Sears Gamefisher) hung on the back. Didn't really want the dead motor, but the PO threatened to charge me extra if I didn't take it. "About three years ago, It just quit and wouldn't start and I had to row in. Don't know what's wrong with it..maybe you could fix it, I'm not mechanical".
So I pulled it off and started fixing up the boat (The plywood seats were rotted out)....but then I got to looking at that sad little Eska girl, and wondering what she needed to make her happy? Kind of like how I can't resist a puppy....
Giving her a few pulls showed the compression was good, but no signs of life. Pulled the (origional, with paint) plug, and it was in good shape and there was spark. A teaspoon of premix in the carby, and the little girl showed signs of life. OK, might be kinda fun to see if I can bring this thing back from "written-off and I'll pay you to take it."
Broke the paint seal on the carb nuts, and found the nastiest mess I have ever encountered in a carb. It was a dry brownish foamy stuff everywhere. No gas would flow through the inlet fitting even...couldn't even get a bicycle spoke through, had to use a drill bit.
Cleaning the bowl revealed the holes eaten through the bottom where nobody had EVER dumped water out. Broke the carb down and soaked it in the canned cleaner. It cut the muck, and also took most of the paint off...didn't seem to hurt anything vital though.
So it turns out we have a dead lawn mower with a Tecumseh I haven't got around to taking to the dump yet, and I recalled that I had put a new float and needle on it not too long before we replaced it, and danged if they and the carb bowl weren't the same as this boat motor has! Put the clean carb back togethor with the seat, needle, float, and bowl from the old lawnmower.
I managed to tear the pump element taking it out (the brown goo was holding it in pretty tight) and the valve membrane and gasket weren't too great, so I ordered those from an online vendor. Set everthing up per a Tecumseh carb manual I found online.
She hit on the first pull with full choke, and on the next pull with half choke she was running and smoothed right out as she warmed up. Seemed to have lots of power(near as you can tell running in a barrel) but wouldn't really idle down. The idle needle didn't seem to matter where it was set within the range of the stop plate. Really didn't want to run slow enough to troll with, and would even be fussy coming up to a dock...especially since this is a fixed gear (no neutral, spin it for reverse) motor.
I didn't have a new 7/16" Welch plug for the idle circuit area when I cleaned the carb, so I had just done the best I could with spray carb cleaner. The spray tube that comes with the carb cleaner fits into the idle air intake real nice, as does the tube for the canned air to dry it out with. Managed to get carb spray coming out all the holes (fuel pickup, air intake, needle hole, two transition ports) though....but I figured there was still some muck in there blocking the idle circuit.
The guy at the lawnmower and chainsaw shop didn't have a plug by itself, but he had a kit with the plug and some gaskets I should have replaced anyway for ~ $5.
I pried the Welch plug out and found the idle circuit was pristine....gave it a scrubbing anyway, and made sure I could see daylight through the little transition ports. Installed the new Welch plug, and sealed it with some of Susan's nail polish. (Now I just need to come up with a good story for the greasy thumb print on the bottle!)
Still no idle. When it died slow, it wouldn't restart without a prime (Either a squirt of gas or a pull with choke) so I figured it must be lean at the low end.
I had put the idle needle stop plate back where I found it....about 3/4 turn out. The guy at the small engine place said most Tecumsehs liked about 1-1/2 turns. So I moved the stop plate some, and at ~1-3/4 or 2 turns was able to get it to run down almost slow enough to count the revs...shakes a lot running that slow, but otherwise happy. Good transition to mid throttle too. Now adjusting the low speed needle makes a difference...yeah!
Ahh, but for every silver lining there must be a cloud: now it 4 cycles above about half throttle. Runs better when cold than hot, and gets worse if I hold my finger in front of the intake, so it must be rich...did I mention I live at almost 5000' altitude?
So I'm thinking somebody in the past had set the idle needle down to almost closed to compensate for over-rich main jetting. Now that I have the idle circuit set where it belongs, she's getting way too much gas when the main jet comes on line.
This carb has a non-adjustable main jet. It is the sort with the jet as part of the bowl nut. It is stamped 39, but this doesn't fit with anything in the tecumseh carb manual, though it does talk about this carb as a "type 2".
The carb kit I bought to get the Welch plug came with an adjustable main jet, and low speed needle, but but they don't fit this carb.
I have made jets in the past...lived my whole life at altitude, but this one is more brass than I want to buy, and more complex than I want to spend time on the lathe.
So my plan is to measure the jet with pin guages, then solder a wire in the existing jet and drill a new hole with about 20% less cross section area (based on experience with motorcycles at this altitude). Yes, I have some microdrills, and a dremel press to spin them fast enough not to break. If it doesn't work, I can solder up the new hole and go back to the old one.
Anybody see a problem with this plan, or know where I can find info and parts (hopefully cheap, 'cause I'm that way*) to "do it right" as far as re-jetting?
*A can of carb spray, Carb dip, carb parts, and a chunk of fuel line, and I'm up to about $35-40 into this motor, and we all know that is a big chunk of what they are worth. Does my heart good to bring a machine back from the dead, but have to be reasonable about it.
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