New question on 1965 Ducktwin 3hp

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mark38090

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I have rebuilt damn near everything except foot and powerhead, still having an issue with running consistently. Last week I pulled the intake and reed plate and checked everything there. I found the vent hole on the reed plate was completely stopped up and cleaned that up, i flipped the reeds over so that they have no play in them. That helped it run consistent, it no longer surges up and down, however it still doesn't rev up like it should. The original cylinder head had a repaired spark plug thread, some kind of insert, so I replaced the cylinder head monday, didn't make any difference. I did however notice that as the fuel got lower in the tank, the engine revved higher and almost ran as it's supposed to. So my question is this, Is it possible that by replacing the the filter inside the tank with an inline filter, could i have restricted the fuel flow and therefore have the carb starving for fuel? On the tank side of the filter I can see air bubbles int he line, the carbn side doesn't have any, does this matter? I'm baffled!!

Original post
http://forums.iboats.com/showthread.php?t=504486&highlight=ducktwin
 
HighTrim

HighTrim

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Re: New question on 1965 Ducktwin 3hp

Is there any way you could post a video of it running so we can tell what is going on?
 
nwcove

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Re: New question on 1965 Ducktwin 3hp

will fuel flow well if you disconnect the fuel line from the carb?
 
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boobie

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Re: New question on 1965 Ducktwin 3hp

One little thought, you're never supposed to flip reeds over because they have taken a set.
 
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mark38090

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Re: New question on 1965 Ducktwin 3hp

I will post video later. If I disconnect the fuel line from the tank it flows from the petcock fairly freely, but definitely not as free from the filter end. As far as flippping the reeds, I was told that your should flip them once they get old because they become weak and don't close all the way anymore.
 
kfa4303

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Re: New question on 1965 Ducktwin 3hp

I gotta agree with Boobie. The reeds almost never "wear out" and you generally want to leave your reeds alone, particularly after they've seated. By flipping them they probably will not close as well/tightly and you risk weakening them which could cause them to break. Is there any way you can by-pass the stock filter and use an aftermarket filter like the one in the pic below? I use them on all of my motors from 3-33 hp.

in-line fuel filter.jpg

This link may help too.

http://www.outboard-boat-motor-repa... Johnson 3 HP 1952-1967 Tune-Up Procedure.htm
 
nwcove

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Re: New question on 1965 Ducktwin 3hp

kfa4303 said:
I gotta agree with Boobie. The reeds almost never "wear out" and you generally want to leave your reeds alone, particularly after they've seated. By flipping them they probably will not close as well/tightly and you risk weakening them which could cause them to break. Is there any way you can by-pass the stock filter and use an aftermarket filter like the one in the pic below? I use them on all of my motors from 3-33 hp.

View attachment 172384



This link may help too.

http://www.outboard-boat-motor-repa... Johnson 3 HP 1952-1967 Tune-Up Procedure.htm
Click to expand...

i think the op did replace the filter with an inline type, and is wondering if it could be restricting fuel flow and causing his issue.
 
kfa4303

kfa4303

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Re: New question on 1965 Ducktwin 3hp

I see. I suppose it could, but I've never had an issue with them. I currently use them on my little gravity fed, 3 hp Gamefisher and my 20 hp without a problem :/ I guess the only way to be sure is to remove, or replace it to see if it makes a difference. The bubbles show that there is obviously and air leak somewhere in the line. Are there fasteners (zip ties, pipe clamps) on the fuel lines to keep them nice and tight? Is there any way to remove the in-tank filter and clean it? You could run a little experiment and bypass the filters all together by putting some fuel mix into a separate container and running a fuel line directly to the carb. If the motor runs well at that point, you know it's a fuel filter issue, if not then it may be in the carb and/or ignition.
 
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mark38090

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Re: New question on 1965 Ducktwin 3hp

That's the exact filter I have on there right now. I removed the in-tank filter completely. Tomorrow I'm gonna try and remove the filter and put a nipple in an old plastic gas can and run it directly to the carb. I will post video of it if it doesn't change anything. Not sure where in North Fla you are but I'm an hour south of Jax. Nice to see another local on here.Stay tuned for tomorrows episode. :)
 
kfa4303

kfa4303

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Re: New question on 1965 Ducktwin 3hp

I'm actually in Tallahassee (Go Noles!). There are quite a few of us "Real Florida" folks here in the forums. We'll have to have an N. FL iboats rally one day! Thankfully, the fuel system on your motor is dead simple, so it can only be one of a few things. Good luck. Keep us posted!
 
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mark38090

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Re: New question on 1965 Ducktwin 3hp

Seems to be running good this morning, I didn't do anything...
 
kfa4303

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Re: New question on 1965 Ducktwin 3hp

Cool. Looks and sounds good to me too. Do not question the Boat Gods! :) Can you get it to idle lower than in the vid? It should get nice and low.
 
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mark38090

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Re: New question on 1965 Ducktwin 3hp

It's on my 10'6" Basshunter EX, top speed today on gps 4.5mph and I can idle it all the way down until the gps reads 0. Check out the weedless foot at about 1:12 in the video.
 
nwcove

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Re: New question on 1965 Ducktwin 3hp

looks like ya got rid of the gremlins!!! motor sounds good.
 
kfa4303

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Re: New question on 1965 Ducktwin 3hp

She's a beauty! A true fire breather. Gotta love that smooth OMC burble at low idle. Best of all, you can now fix virtually any OMC motor from the same era. They're basically just larger and smaller versions of each other. Be careful these old motors are great conversation pieces and total check magnets, so allow for a little extra time at the boat ramp to chat with your adoring public :) Happy boating. Vroom-Vroom!!!
 
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