Old Evinrude 10 HP; starts but won't stay running. PLEASE HELP!

I already missed opening weekend for duck season in Minn. and I'm hoping to get out this weekend but need a working motor. I have a 1956 Evinrude 10 HP outboard. I cleaned the carb, replaced the plugs, and replaced the fuel line. The motor starts up fine. Sometimes I can give it full throttle and it only runs at roughly a half throttle speed but after about 15 seconds it will kick in and the RPM will move up to full throttle where they should be. After about3 or 4 minutes of running the motor it slowly dies. The motor will start up fine the next time I pull it. Please let me know your thoughts. I know some about motors but I'm not an expert. Thanks!

Re: Old Evinrude 10 HP; starts but won't stay running. PLEASE HELP!

Ok .. This may sound very elementary, but I was doing these are some basic things I would check.

1) Make sure your gas mixture is good, and not old.....
2) Check your gas bulb, hose and connections (Sounds like you already did this)
3) The air mixture may be too lean on your setting. This was happening with my outboard. I slowly turned the dial counter clockwise and it ran better. Too lean will cause it too overheat too (I hear)
4)Make sure your choke is turned back to run position after start.

Somebody please chime in. I'm a newbee here........

Re: Old Evinrude 10 HP; starts but won't stay running. PLEASE HELP!

Sounds like you may have a coil cutting out when it warms up - that would explain the running at half-throttle then speeding up. A second thing to check is the water pump. Is it pumping ok? Overheating will cause motor to shut down. How is your pressure tank? Is it developing pressure? It should hiss or whoosh out pressure when you unscrew the gas cap. Motor has no fuel pump and depends on that pressure in the tank to feed gas to the carb. When it starts to die, pump the primer button and see if keeps running.

Re: Old Evinrude 10 HP; starts but won't stay running. PLEASE HELP!

I replaced the gas a couple times. The first time I had premium gas from a gas station and I currently am using nonoxygenated gas without enthanol becuase I heard some old motors can't handle the excess amount of oxygen the alcohol produces. There is no gas pump on the motor. It uses a gravity feed with the gas tank built into the top of the motor. I will check the coil. If the coil is cutting out does that call for a new coil? The motor is from '56 I bought it for $65 so I'm completely fine with putting some money into for the price I paid and the amount of money I had set aside for a motor but I just want to make sure I'm able to find a new coil without paying an arm and a leg. If there is anything i need to do (clean, tighten, etc.) please let me know! Thanks!

Re: Old Evinrude 10 HP; starts but won't stay running. PLEASE HELP!

You can replace everything under the flywheel - points, coils, condensers and wires, for less than what you paid for the motor.

Also, that motor uses a pressure tank fuel system. Make sure your tank has good hose, good o-rings in the connector, and is clean inside. Cap should be tight when running.

Re: Old Evinrude 10 HP; starts but won't stay running. PLEASE HELP!

wsubaseball7 said:

There is no gas pump on the motor. It uses a gravity feed with the gas tank built into the top of the motor.

Click to expand...

The 10hp has an external fuel tank. The only motor with a built-in tank on top (in 1956) is the 3hp.

Re: Old Evinrude 10 HP; starts but won't stay running. PLEASE HELP!

Hi wsu. The previous postst are right. Because the motor is '56 model you'll need to use the old style, two-line, pressure tank system. If you can't find one, don't worry you can actually convert your motor to a modern single-line set up, pretty easily. I have a '61 10 hp I recently brought back to life. Great little motor, and well worth the effort. Give these links a read. They can walk you through a basic tune up and servicing of you motor. You probably want/need to get new points and condensers ($20), new impeller ($20), new 7mm copper core spark plug wires ($3 a foot x 10 ft = $30), and a carb kit ($25). For less than $100 you can rebuild ritually the entire motor and she'sll be ready to run for another 50+ years. Give 'em a read and holler back.

http://www.sschapterpsa.com/ramblings/johnson_QD.htm
http://www.duckworksmagazine.com/07/columns/max/index1.htm
http://www.outboard-boat-motor-repa...on 3 HP 1952-1967 Ignition System Tune-up.htm
http://www.sschapterpsa.com/ramblings/Converting_dual_fuel_line.htm
http://forums.iboats.com/showthread.php?t=167352

Re: Old Evinrude 10 HP; starts but won't stay running. PLEASE HELP!

........oh btw, you can get all of the Sierra brand replacement parts right here at iboats and/or at your local NAPA auto parts store. If they don't have the part in stock at NAPA, they can have it delivered to the store by the next day for FREE!

here's a link with exploded diagrams and part numbers for your entire motor. the part numbers listed are the original OMC numbers, most of which have now been replaced by Sierra brand parts whose numbers usually start with 18-XXXXXX. You can use iboats to double check/cross reference the part numbers.

http://www.marineengine.com/parts/v...ntage-evinrude-johnson/376747/37674700001.htm

Re: Old Evinrude 10 HP; starts but won't stay running. PLEASE HELP!

Let's back up a bit. You mention a gravity feed tank? That would make this something other than a 1956 model 10hp ? if it is original. Any chance this motor has been modified with the built-on tank? It would have originally had a pressure feed system with a dual-line tank IF it is a 1956. Gravity feed 10hp models were from the 1940s & prior, like the Lightfour models.

Please post your model number so we can get a better idea of what you actually have...