'63 Evinrude 40hp big twin wont rev up

Hello fellow boaters.

I just bought my first boat. I know nothing about 2 strokes or marine engines. What I do know is this motor has specs regarding "4500 rpm" which mine comes nowhere near lol. I found a service manual for it online. No matter how I adjust the linkage, the throttle valve on the carb never opens, which to me explains why the engine never revs up.

I bought the boat from a young guy who was trying to pull a heavy group of friends on tubes and was trying to get as much out of it as he could. He owned it for a year and said it ran properly when he got it. I started from scratch on the fuel mix setting on the carb and some new fuel that I know is mixed properly and it ran better but that throttle just wont open up.

Any advice would be appreciated. Thanks and happy boating!

Re: '63 Evinrude 40hp big twin wont rev up

Welcome to iboats

As you advance the throttle the linkage should be moving rotating the armature plate to advance the timing. there is almost no movement of the carb valve during the advancing of the spark. Once the armature has reached full advance by means of contacting a stop, the throttle linkage should be making contact with a collar on a rod that is linked to the throttle valve on the carb. the throttle linkage wll now be pushing againt a spring on the linkage to the armature as is moved to wide open. You say you have a service manual, that description, or something like it, should be in there, as well as how to adjust it properly. If the points are out of adjustment that can cause low power too, as can low compression.
The 4500 rpm, that is, rated 40hp @ 4500. operating range 4000-5000 rpm. Meaning it makes 40hp at 4500. At WOT it should be propped to run between 4000 to 5000 rpm.

Re: '63 Evinrude 40hp big twin wont rev up

Thanks Jimmbo. I had a feeling I might be chasing rainbows with that throttle movement. Time to check out the points and confirm my compression.
One other question. The throttle position lever where the throttle cable attaches shows "slow, start and fast" positions. The start and fast positions are fine but that lever won't ever go back to the slow position. What is that slow position for and is there a reason it won't go back to that position?

Re: '63 Evinrude 40hp big twin wont rev up

HI fro. Welcome to iboats. Here are some handy links to help you get her up and running right. While the "Slow, Start, Shift" positions are only approximate, you can get further range of motion out of the throttle by adjusting the idle set screw found at the base of the vertical throttle tower the tiller ultimately attaches to. Twisting it in, advances the timing slightly to raise the idle rpms, while backing the screw out retards the timing slightly, thereby lowering the rpms at idle. You should be able to get most routine, consumable parts right here at iboats. There are really only 3 things you need to get the old gems to run right. 1.) Compression (+100 psi with cylinders within 10% of each other) 2.) Spark ( should be able to consistently jump a 1/4" gap using a gap tester from the auto store ($5) with a bright blue snapping spark.) 3.) Fuel (throoughly clean and rebuild the carb and replace any old fuel lines as needed.) Confirm each of these aspects before moving on to the next and you'll have her up and running in no time. Good luck. Holler if you get stuck.

http://www.duckworksmagazine.com/04/s/columns/max/24/index.cfm
http://forums.iboats.com/showthread.php?t=158086
http://www.marineengine.com/parts/v...ntage-evinrude-johnson/379272/37927200001.htm
http://www.outboard-boat-motor-repa...on 3 HP 1952-1967 Ignition System Tune-up.htm
http://www.outboard-boat-motor-repa...hnson 5.5 HP 1954-1964 Carburetor Tune-UP.htm

Re: '63 Evinrude 40hp big twin wont rev up

Had the same problem today on same motor, The butterfly behind the choke was not opening, stuck shut, a pair of needle nose pliers and some WD-40 and a few minutes later it runs like a dream.

kfa4303 said:

HI fro. Welcome to iboats. Here are some handy links to help you get her up and running right. While the "Slow, Start, Shift" positions are only approximate, you can get further range of motion out of the throttle by adjusting the idle set screw found at the base of the vertical throttle tower the tiller ultimately attaches to. Twisting it in, advances the timing slightly to raise the idle rpms, while backing the screw out retards the timing slightly, thereby lowering the rpms at idle. You should be able to get most routine, consumable parts right here at iboats. There are really only 3 things you need to get the old gems to run right. 1.) Compression (+100 psi with cylinders within 10% of each other) 2.) Spark ( should be able to consistently jump a 1/4" gap using a gap tester from the auto store ($5) with a bright blue snapping spark.) 3.) Fuel (throoughly clean and rebuild the carb and replace any old fuel lines as needed.) Confirm each of these aspects before moving on to the next and you'll have her up and running in no time. Good luck. Holler if you get stuck.

http://www.duckworksmagazine.com/04/s/columns/max/24/index.cfm
http://forums.iboats.com/showthread.php?t=158086
http://www.marineengine.com/parts/v...ntage-evinrude-johnson/379272/37927200001.htm
http://www.outboard-boat-motor-repa...on 3 HP 1952-1967 Ignition System Tune-up.htm
http://www.outboard-boat-motor-repa...hnson 5.5 HP 1954-1964 Carburetor Tune-UP.htm

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Re: '63 Evinrude 40hp big twin wont rev up

awesome. gotta love it when it's something simple (and cheap). It usually is on these old gems. That's half the the beauty of them. Everything is purely mechanical and can usually be fixed with a flathead screwdriver, a 7/16" wrench and a pair of good 'ol needle nose pliers

Re: '63 Evinrude 40hp big twin wont rev up

Thanks to everyone for all the helpfull advice. Turns out the float in my carb was saturated. Carb kit on order. Leg filled up with water to so I tore the whole thing apart. Great learning experience. Should be screaming across the lake in no time. Happy boating y'all. And remember, you can't catch fish with your rod on the floor. Cheers!