Poppet Valve Service

[slim60]

I have a 1922 Evinrude model A. It has good commpression and spark and NOS spark plug. I put my last OMC packing washers in the poppet valve and a few drops of penetrating oil in it because the primer button is stuck. I could use any info on starting procedure, maintenance, etc. Thanks, Slim

[PM T2]

Poppet valve has to move freely. You have to lift it by pushing on the stem from underneath. The poppet valve is spring loaded and needs to have pressure on it when you lift it off the seat. There is no primer button on that mixer.

Best way I’ve found to start those things –
1. open the fuel inlet valve that should be on the tank, then
2. open your needle valve about 1/2 to 5/8 of a turn, then
3. lift the poppet valve off the seat and let a few drops of fuel leak out.
4. Bounce the flywheel back and forth several times between compression to prime the crankcase, 5 or 6 times might be enough, if not you can do it more on the second attempt
5. Move the timer lever so that it is slightly to the port side (your RH side, if you are standing in front of the motor) of the centreline of the cylinder – in other words, around the 5 o’clock position, then proceed to
6. Pull the flywheel over through compression and see if it will bark for you.

Once the engine starts, it is normal to have to adjust the needle valve slightly toward the lean side to get her to smooth out.

Hope this helps.

best,
PM T2

He's livin' in his own private Idaho..... I hope to go out quietly in my sleep, like my grand-dad did..... and not screaming, like the passengers in his car...

[PM T2]

Maintenance – as long as the spring is present, and does exert some pressure on the poppet valve, don’t worry too much about actual spring pressure unless you really have to (i.e. motor just will not start, etc).

Spring can be on the stem of the poppet valve (if so, it will have to be kept in place with a washer and retaining pin (cotter key)), if installed in this manner the spring will be pulling the poppet valve shut against its seat; or, or it can be inside the mixer, so it pushes against the underside of the removable cap and exerts pressure on the poppet valve from the top side.

Stem fit – sometimes these get sloppy, if there is some clearance between the valve stem and its guide it should still run for you, but if it gets bad enough and the clearance is much too large it can affect how well the poppet valve will seat while in operation.

Normally I don’t recommend anything too aggressive be done to the poppet valve or the seat. Cleaning with a Scotchbrite pad is all that is normally needed. In cases where there is severe scoring or wear apparent, you can make up a lapping compound out of toothpaste and Comet cleanser and lap the surfaces much in the same way you’d lap the valves and seat on a four-stroke internal combustion engine. Make sure you wash away all traces of your lapping compound if you do this.

Hope this helps eh

best,
PM T2

He's livin' in his own private Idaho..... I hope to go out quietly in my sleep, like my grand-dad did..... and not screaming, like the passengers in his car...

[jeff-register]

Yes I was going to say lap in the poppet valve. Auto supplys have finishing compound to lap it in. They also have a small wooden handle with a suction cup on it for laping. If your guide is oversize you can have it knurlded at the auto supply. It expands the metal to bring it back to factory specs. After lap it in & should have a dull grey color to the seat area without any changes. It will be new again after that.

[slim60]

Poppet valve is clean and free. Fuel comes out when pressed up. Does it matter which end of spring goes up? Small end was up but seems to fit better small end down. Fuel shut off stem is broke but got it open. Cleaned the filter but gasket fell apart on screw. Will a cork gasket work? Anyway I turned the flywheel back and forth three times and it fired…once. It fired again but just once about every third time. Motor was mounted on a sawhorse so it was not level. New water hoses so I could try it leveled in the test tank after I fix that leak. This thing is heavy so anymore advise would be very much appreciated before my pore aching back has to lift it into the tank. Thank you all. Slim

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[Tubs]

A "Boat House Repair" is one that done without having tools or the skills to do it properly.

• This reply was modified 6 years, 1 month ago by Tubs.
• This reply was modified 3 years, 10 months ago by Tubs.

[PM T2]

Poppet valve setting – I usually open the knob/handle thing until it butts up against the stop pin. Normally, that’s all it needs. On my early Evinrude that doesn’t have the stop pin on the mixer valve cap, I open it about 3/4 to 7/8 turn and leave it there, she runs just fine that way from start-up to shut-down.

Needle valve – these have a coarse thread needle so you don’t want to turn it open very far…. if it coughs every time you pull it but won’t keep running, try shutting the needle valve off completely, pull it over, and see if it fires up again and acts like it really wants to run until the fuel runs out (only takes a few seconds)…. if that’s how it acts, you know your initial needle valve setting is too rich. I usually go open 1/2 to 5/8 turn to start, then lean it out from there to get her running smooth.

Hope this helps.

best,
PM T2

He's livin' in his own private Idaho..... I hope to go out quietly in my sleep, like my grand-dad did..... and not screaming, like the passengers in his car...

[slim60]

After nine bounces she started and ran for 20 seconds when I noticed no water from the exhaust. I ran some water then air through the hose and she pumped on the next two runs about a minute each time. The fuel tank leaks bad so that will be a starting point. Thanks PM T2 for the start sequence. Slim

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