1959 35hp johnson super seahorse - carb problems

Frechettem

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Aug 30, 2013
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I have a 1959 35hp johnson super seahorse that was running good until I took the carb apart to replace the gasket.I didn't alter anything else and put it back together. When I went to start it, after many pulls, with would run for only a few seconds and die. I took the carb apart again to make sure everything was in order and did a good cleaning. But still the same outcome, it will run for a few seconds and die. Not sure what to do next. I feel like it has to be something simple. Thank you for any suggestions.
 

F_R

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Re: 1959 35hp johnson super seahorse - carb problems

How far open do you have the needles?
 

kfa4303

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Re: 1959 35hp johnson super seahorse - carb problems

Hi Frechettem. Welcome to iboats. Cool old "Big Twin" motor you've got there. Here are some handy links that will familiarize you with your motor as well as walk you through a complete carb rebuild.

Reviving a Vintage Big Twin - Part 1 (general info)
5.5 HP Evinrude Johnson 1954-1954 Carburetor Tune-Up Procedure (Carb rebuild link. It's for a slightly different model, but all of the steps will apply to yours as well.)
http://forums.iboats.com/engine-fre...sorted-carb-variations-joe-reeves-167352.html
1959 Johnson RD-21 35 hp Outboard Motor Parts
 

Frechettem

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Re: 1959 35hp johnson super seahorse - carb problems

How far open do you have the needles?

I removed them when I cleaned the carb but I put them all the way in and backed them out about a turn and a half. Is this a good starting point?
 

kfa4303

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Re: 1959 35hp johnson super seahorse - carb problems

Hello again Frechettem. Here's a great link for dialing in the carb. You generally want to start the lo speed needle out about 1 1/2 turns from lightly seated, while the hi speed needle usually starts about 1 full turn out form seated. Of course, you'll need to adjust them in the test tank and again on the open water, but it will get pretty close.

(Carburetor Adjustments - Two Adjustable N/Vs)
(J. Reeves)

Initial settings are: Bottom high speed = seat gently, then open 1 turn out. Top slow speed = seat gently, then open 1-1/2 turns.

Setting the high and low needle valves properly:

NOTE: For engines that DO NOT have a shift selection, obviously there is no NEUTRAL position. Simply lower the rpms to the lowest setting to obtain the low speed needle va /lve adjustment.

(High Speed) Start engine (it will run pretty rough), shift into forward gear, take up to full throttle. In segments of 1/8 turn, wating for the engine to respond between turns, start turning in the bottom high speed needle valve. You'll reach a point whereas the engine will either start to die out or spit back (sounds like a mild backfire). At that point, back out the needle valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest setting.

(Low Speed) Slow the engine down to where it just stays running. Shift into neutral. Again in segments of 1/8 turns, start to turn the top needle valve in. Wait a few seconds for the engine to respond. As you turn the valve in, the rpms will increase. Lower the rpms again to where the engine will just stay running. Eventually you'll hit the point where the engine wants to die out or it will spit back. Again, at that point, back out the valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest slow speed setting.

When you have finished the above adjustments, you will have no reason to move them again unless the carburetor fouls/gums up from sitting, in which case you would be required to remove, clean, and rebuild the carburetor anyway.
 

Tom Maslar

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Jul 29, 2011
Messages
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Re: 1959 35hp johnson super seahorse - carb problems

It looks like you are not getting fuel ,so from the sequence of events you described, in all likelihood there has been an error in the carb work that inhibits fuel flow. The links Kfa[SUB][/SUB] provided should help.
 
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Tom Maslar

Petty Officer 2nd Class
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Jul 29, 2011
Messages
137
Re: 1959 35hp johnson super seahorse - carb problems

Also possible you picked up a peripheral problem which is unrelated, but inhibits fuel flow.
 

HighTrim

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Jun 21, 2007
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10,486
Re: 1959 35hp johnson super seahorse - carb problems

The needle is stuck in the seat, float sinking, float catching on the gasket, float pin no spinning or nicked, vent obstructed, boss gasket, etc..
 
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