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- This topic has 10 replies, 6 voices, and was last updated 6 years, 2 months ago by
Geer Pyron.
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April 30, 2019 at 5:43 pm #174572
I have finally gotten my first ever old outboard project done. By done I mean I put it on a boat and went for a ride! Ha!
It was nice. I learned a lot.
But I casually mentioned to a friend that I had modified the…. the…. brass stopper that is mounted under the armature plate.
I filed a section of it so that when in forward I can open the throttle more when in gear.
he looked at me funny and said, “oh, well, hmmmmm. I don’t know that you shoulda did that. Hmmm.
I think that’s a question for the forum. ”
So here I am.
He was gonna use the motor for an excision.
I thought it’d be wise to let him know.
Now I’m worried.
But thinking about it, why would it be an issue?
The butterfly inside the carb now opens all the way.
Plus, I barely had to file any off, maybe 1/32, maybe to get it past the gear shift link. It was barely hitting it. As if something was just a little off.
Anyhoo, any cautions, advice?
I’ve got oodles of this things so it’s no big deal, I just don’t want my first motor rebuild to be a total failure when it blows up (or whatever outboards do when they suddenly and catostrophiclly fail) in the
middle of the lake.
Ha!
Thanks,
Geer in G’villeFLJMGP
April 30, 2019 at 6:36 pm #174576What you did was allow more spark advance than what the factory allowed. It might actually slow down some if you have too much advance. But worse, it could burn a piston from pre-ignition.
April 30, 2019 at 8:49 pm #174581Okay!
That’s what I wanted to hear.
And makes sense cause thinking
On it now I know that the cam is not actually moving any more, but the armature plate is rotating(advancing).
Okay.
Bare with me.
Thanks.
But as an aside, he did take it out on the Suwannee today and ran 20 miles at WOT and said it was a dream.
G
But I will put it back to the way it was just to be safe.
ThanksJMGP
May 1, 2019 at 6:09 am #174600Fastwins are my favorite non-square tank motors, enjoy it 😉
Rotary valve Johnson’s Rule!
May 1, 2019 at 6:57 pm #174641Why don’t you post a picture of exactly what you filed…. From what you have written, it would seem like you ground the brass notched cam that hits the vertical shift interlock rod…. But, I’m guessing you ground something else that actually allows a little more spark advance and opening the butterfly a bit more. Sounds like you ground “just a little bit”, but that could be enough to cause detonation/preignition….
Did you notice any change in WOT performance. In actuality, you did make an attempt to address a bit of an engineering flaw. Altering cam pick up adjustments can also affect WOT butterfly positioning, which there is no way to adjust…. Perhaps your throttle cam pick up is not set correctly, or the rubber cam follower roller is worn/grooved keeping the butterfly from opening fully….May 1, 2019 at 9:35 pm #174650Fleetwin,
I will make an attempt at posting photos tomorrow.
I’ve got to learn how.
But yes, you get what I did.
Everything was set as it should be and the cam follower is not worn/grooved.
I made it. From some rubber and nylon.
As far as it affecting performance at WOT, I couldn’t answer that. I did the mod before I ran it for the first time. My friend who ran it for an extended period did say it ran well though.
I’m sorry I don’t have my terminology exactly right
Which makes me mad and must drive you guys crazy, but I’m fairly new to this.
Thank you for the input.
GJMGP
May 1, 2019 at 9:37 pm #174651PS What is a non square tank motor?
GJMGP
May 2, 2019 at 10:02 am #174672Square-tank motors or “square-tankers” is what we call the antiques that have a square-ish fuel tank mounted to the motor itself. Typically a pre-war, open flywheel, direct-drive outboard with a rope-sheave or a knob on the flywheel for starting. This term typically covers most pre-WWII outboards back to and including RBMs (RowBoat Motors). RBMs are really their own category / subcategory though. These are the earliest of the outboard motors and they have a very devoted following.
-BenOldJohnnyRude on YouTube
May 2, 2019 at 11:50 pm #174737Anonymous
Is your home made cam follower roller the same diameter as the original factory roller?
May 3, 2019 at 9:55 pm #174799Not to worry buddy. Your terminology is fine, but the written words are often confused, so I just want to make sure I’m sure I understand what you are explaining so I don’t confuse the issue further…..
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