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1956 Evinrude Big Twin 30hp timing

P

powellc002200

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Does anyone know what the timing specs should be for this engine? I'm guessing that it may be 2 degrees ATDC at idle and 28 degrees BTDC at WOT but I can't find confirmation.

Thanks for your help!
 
The timing on those old motors aren't adjustable. The timer bases just come to a stop molded into the block. And that takes care of the full spark advance timing.

Just set the points with the points fiber rubbing block in line with the flywheel key so that a .020 gauge will go thru but a .022 will not.

Adjust the throttle roller so that the throttle butterfly just starts to open when the scribe mark on the cam that rolls against it is dead center with the roller.

That'll have your timing, linkage, and synchronization as close as the factory could ever get it.
 
On those engines the sync is done tith the pointer on the intake manifold not the roller. Just to the left of the roller is a pointer that is just off center of the carb. Line the mark on the throttle cam with the pointer and the roller should be just touching the cam. The carb should begin to open as the mark passes the pointer.
 
Once you get the sync correct you adjust the link. There is a brass collar on the link rod going under the flywheel loosen that screw then shift into forward gear engine off. You may need to spin the prop to go into gear. Then yo put the engine into the WOT position. With one finger fully open the carb and then push the collar all the way up to the pivot pin and tighten the screw. That should hold the carb fully open. Then check your work take it to idle speed and then slowly give it throttle the carb should just begin to open as the mark passes the pointer and then be fully open at WOT?
 
Those flywheels have a access port for adjusting the points. The most accurate is with a timing light just shine the light at the two marks on the side of the points plate (armature plate). The single mark on the flywheel should be inbetween the two marks on the plate? It can be time consuming and make sure your feeler guages and points are nice and clean. All it takes is a little skin oil to fry the points. When everything is good you can idle those motors down to a slow crawl. You want to run 24:1 oil mix so keep a set of plugs and tools handy as they tend to foul plug fairly often do not attempt 50:1 mix or you will be looking for another motor shortly after.
 
I should say that my Lark 40 hp has been running with Amsoil, fully synthetic pre mix at 64:1 since 1978, but that is just me. If you want to be extra careful you can run at 50 to 1. These techs here are so great, I love these guys, don't want to "ruffle" their feathers. They are not as open to leaning down these old motors. I'll tell you what, you go get some Amsoil Saber 2 stroke pre mix, and mix it at 50:1 with non oxy fuel. If you toast the powerhead on that old boat anchor, just send it to me. I have 4 of these powerheads for your motor, they are pristine. I will send you a pristine 30 hp 1956 or 57 powerhead, plus 100 bucks for your trouble. Google up "Raquel and Tim's Timber" in Duluth MN. Just make sure you have a good powerhead to begin with. Like to see 100 psi or better on warm compression test, throttle open, both plugs out, pulling very swiftly. Remember, some models had a decompressor when using the recoil, you will have to defeat that for your compression test. Make sure you have a good rope on it.
I love to run my vintage outboards, but can't tolerate people scowling at the smoke. I don't have to create a problem and make these sweet motors a bad name. People are amazed when they witness such a great running outboard that is 60 years old. That's why I do it. This is true, reliable, trustworthy engineering. I do it to proove that.
 
Last edited:
joereeves said:
The timing on those old motors aren't adjustable. The timer bases just come to a stop molded into the block. And that takes care of the full spark advance timing.

Just set the points with the points fiber rubbing block in line with the flywheel key so that a .020 gauge will go thru but a .022 will not.

Adjust the throttle roller so that the throttle butterfly just starts to open when the scribe mark on the cam that rolls against it is dead center with the roller.

That'll have your timing, linkage, and synchronization as close as the factory could ever get it.
Click to expand...


Thanks! I guess that explains why I couldn't find anything.
 
kimcrwbr1 said:
Once you get the sync correct you adjust the link. There is a brass collar on the link rod going under the flywheel loosen that screw then shift into forward gear engine off. You may need to spin the prop to go into gear. Then yo put the engine into the WOT position. With one finger fully open the carb and then push the collar all the way up to the pivot pin and tighten the screw. That should hold the carb fully open. Then check your work take it to idle speed and then slowly give it throttle the carb should just begin to open as the mark passes the pointer and then be fully open at WOT?
Click to expand...

Thanks again - I will give that a try.
 
kimcrwbr1 said:
Those flywheels have a access port for adjusting the points. The most accurate is with a timing light just shine the light at the two marks on the side of the points plate (armature plate). The single mark on the flywheel should be inbetween the two marks on the plate? It can be time consuming and make sure your feeler guages and points are nice and clean. All it takes is a little skin oil to fry the points. When everything is good you can idle those motors down to a slow crawl. You want to run 24:1 oil mix so keep a set of plugs and tools handy as they tend to foul plug fairly often do not attempt 50:1 mix or you will be looking for another motor shortly after.
Click to expand...

Thanks! I've been using a 24:1 oil mix and it seems to be working since I still have 110 compression on both cylinders. It's fun to work on these old engines even though it's getting harder to find parts and manuals.
 
Well, you may find that some parts are cheaper and easier to find that parts for much newer motors.----Saw a wanted ad for a 2001 model 25 hp Honda.------CDI ignition module is apparently listed as ---NLA
 
kimcrwbr1 said:
Once you get the sync correct you adjust the link. There is a brass collar on the link rod going under the flywheel loosen that screw then shift into forward gear engine off. You may need to spin the prop to go into gear. Then yo put the engine into the WOT position. With one finger fully open the carb and then push the collar all the way up to the pivot pin and tighten the screw. That should hold the carb fully open. Then check your work take it to idle speed and then slowly give it throttle the carb should just begin to open as the mark passes the pointer and then be fully open at WOT?
Click to expand...

That is incorrect. Contact with the collar happens when control is at full spark advance (not WOT). There is further movement of the control after full spark advance is reached. That further movement causes a cam-over which opens the carburetor all the way.
 
Sticking my two cents worth back in...................

********************
(Synchronization Of Older 2 Cyl Engines)
(Such As The 28, 33, 40hp Etc models )

On the linkage that runs from the armature plate (the plate the coils & points set on) to the carburetor throttle roller, loosen the set screw on the brass collar that you see there and temporarily move it away from the armature plate/vertical throttle arm clevis (clevis is that thing the linkage rod slides through). We'll refer to that vertical throttle arm/armature plate clevis simply as the "clevis" from this point on.

Look at the cam that's attached to the front of the armature plate.... the cam that slides up against the carburetor throttle roller. You'll notice that there's a scribe mark on it. Also notice that at the top portion of the intake manifold there is a raised portion, that top portion forming a point. The carburetor roller should contact the cam and just start to open the throttle butterfly when the scribe mark is dead center with that point.

With the engine in gear (not running of course) have the armature plate advanced all the way (by hand) so that it is up against its stop. Now adjust the brass collar (set screw) on that associated linkage rod so that it is up against the clevis. It should be adjusted so that there is either no play, or just a hairs play between the collar and the clevis.

At this point, the armature plate movement is not advancing the throttle butterfly via the rod movement, but further movement of the throttle control, although the armature plate cannot move any farther, causes the tension spring at the armature plate to allow the vertical throttle arm to move farther which now advances the carburetor throttle butterfly via the rod. When fully advanced (full throttle), the carburetor throttle butterfly should be fully opened (horizontal).

If all else with your engine is as it should be, that should do it.

********************
 
timguy said:
I should say that my Lark 40 hp has been running with Amsoil, fully synthetic pre mix at 64:1 since 1978, but that is just me. If you want to be extra careful you can run at 50 to 1. These techs here are so great, I love these guys, don't want to "ruffle" their feathers. They are not as open to leaning down these old motors. I'll tell you what, you go get some Amsoil Saber 2 stroke pre mix, and mix it at 50:1 with non oxy fuel. If you toast the powerhead on that old boat anchor, just send it to me. I have 4 of these powerheads for your motor, they are pristine. I will send you a pristine 30 hp 1956 or 57 powerhead, plus 100 bucks for your trouble. Google up "Raquel and Tim's Timber" in Duluth MN. Just make sure you have a good powerhead to begin with. Like to see 100 psi or better on warm compression test, throttle open, both plugs out, pulling very swiftly. Remember, some models had a decompressor when using the recoil, you will have to defeat that for your compression test. Make sure you have a good rope on it.
I love to run my vintage outboards, but can't tolerate people scowling at the smoke. I don't have to create a problem and make these sweet motors a bad name. People are amazed when they witness such a great running outboard that is 60 years old. That's why I do it. This is true, reliable, trustworthy engineering. I do it to proove that.
Click to expand...
Hi Tim sent you a friend request on fb. I run an 18 as my daily driver. I switched it to a fuel pump. Will this change the timing at all on the 56 Big twin 30. And have hou ever ran one that way ? Or are you on a two line still. I have the original two line and thought about rebuilding the tank. But I like the fuel pump and ease of use. So I am opting for that option. Tia ✌️
 
Ayerloom said:
Hi Tim sent you a friend request on fb. I run an 18 as my daily driver. I switched it to a fuel pump. Will this change the timing at all on the 56 Big twin 30. And have hou ever ran one that way ? Or are you on a two line still. I have the original two line and thought about rebuilding the tank. But I like the fuel pump and ease of use. So I am opting for that option. Tia ✌️
Click to expand...
it's a 25022
 
Okay I'll look just came back from a roof repair up at Ontario camp near Grassy Narrows. No problem with fuel pump conversion. But I love the two line pressurized systems.
 
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