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63 Johnson 10hp will not open throttle fully

J

Johnboatcaptainron

New member
New to boat motors and this is my first post. Thanks for any help. I just bought two motors, a 50's model evinrude 7.5 and a 63 Johnson 10 hp model qd-24b. The 7.5 came with a good metal fuel tank. Both have good compression and needed some minor stuff. I gave 250 for all. I was told the 10hp was run last year and that's the one I am working on first. The recoil spring was broke and I stole the one off the 7.5. I pulled the flywheel and checked the coils for cracks and cleaned/adjusted the points to .020, they were a little tight. I still need to replace impeller, and get a female adaptor so I can plug up fuel tank, but I could not get the motor to hit at all after spraying a little fuel in cylinder. Before putting it away last night, I noticed something was not right with the throttle linkage. The throttle grip on tiller handle would not turn back past start to get to slow and stop. I thought maybe the little ring with the words was just misaligned. So I twisted throttle to what I thought start should be, and tried starting, and surprise it tried to start. I quit there(I had allready empty my water bucket). I noticed when I twisted the handle all the way, I could still pull the carb linkage over half way. Is there adjustment on that? It looks like the thing under the flywheel that comes all the way around needs to be rotated around some, the fatest part that pushes the little barrel looking thing out is a couple inches away from the barrel.(the barrel looking thing is connected to carb linkage) Sorry I don't know the correct term for this stuff. Don't even see them on the parts diagram.
 
On the 10 hp the motor must be in gear to get full throttle.---------Start with a compression test and report the values you get.--------The other test is for " good spark "-------Does spark jump a gap of 1/4" or more , yes or no ?-------No point in saying that you have good spark.
 
I did a compression check before I bought them. I had to use a ratchet to turn the 10hp because the recoil spring was broke, but still managed to get 66lbs on top cylinder and 62 on the bottom. The 7.5 had 70 on both with a pull rope. I know the ratchet isn't as good as a pull start, so I will check again. Before reseting the points, I had a white spark, now I have a deep blue spark, grounding to the block. I will do the 1/4" test, just ran out of time last night, I believe I read to use a block of wood and two nail 1/4" apart and ground 1 nail with a wire to the block, correct? I believe this old motor will run as soon as I get an adapter to plug in fuel tank, I just don't get much time to work on them between 64 hours at work every week, my older sons base ball practice and a newborn. Should I be able to feel the start, stop, and slow settings in the throttle grip? The only tiller Steer I've ever run was an early 90s mercury 25 when I was a kid and it was totally different(forward and reverse in the throttle grip).
 
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As previously said, it must be in gear to get full throttle. That said, if you have it in neutral, then turn the grip toward "Fast" as far as it will go (in neutral) that is the real "start" position, no matter what it says on the dial. And the only position you can "feel".
No point in trying to start it till you get a proper fuel hookup.
 
Ok, thank you guys. I plan on stopping and getting a fuel hook up before I work on it again. I'm sure I will have more questions, especially when I start on the 7.5. The fuel tank I got was for the 7.5, it has 16:1 in it, I was planing on starting the 10 hp on it, then buying a new plastic tank for the 10. It has a primer button built into the tank and no primer bulb in the line. Is this a pressure tank I hear about for some of these older motors that don't have fuel pumps? Will it still work with the 10hp that has a fuel pump. Should I run 24:1 in the 10hp?
 
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The pressure tank will not work with the 10 hp if it has the fuel pump / single line fitting.--------The 10 hp can be run at 50:1 for " fishing use "------------------If you are running on a 12 foot aluminum or seaflea then more oil will be a good idea.
 
The tank has duel hoses coming out of it, I figured one was a return. It shoots fuel out one hose when you push the button on tank. It will be ran on a 1981 14' aluminum grumman. It measure 14'6" with 5'4" beam. It kinda looks like a tri-hull front end. It's rated for a 25hp and 825lbs people and gear. Hoping it will be a good stable boat for my son and I to fish out of. I've not been able to find any info on these boat.
 
No, one hose is an air pressure hose.----Crankcase compression from motors pre 1959 is used to keep pressure on the fuel so that fuel flows to the motor.-Thus no pump needed.-----That duel hose tank will not work on the 10 hp as it is now.---Modification would be needed.----If it shoots fuel out the hose when pushing the primer button then it may need new o-rings in the fitting.------You should only be able to pump fuel when the fitting is plugged into the correct fitting on a motor.
 
Thanks racerone. That makes sense now, did not now how the tank kept pressure with just the little primer button. Just to clarify, the tank just has two cut off hoses on the end of it right now, did you mean o-rings at the tank, or did you think it already had a quick connect on the end of hoses that needed o-rings
 
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Those fittings with the 0-rings are expensive if you can find one.----No doubt it was cut off and sold.--------The primer button is used to pump fuel to the motor.-----The primer button does NOT pressurize the tank.
 
Ok, bought a new tank and fuel line for the 10hp today. Got home and hooked it up, primed the bulb, and, no start. Checked compression again with the pull rope, got 75lbs bottom and 70lbs top. Did it 3 times each cylinder and got the same results every time. Did a spark gap test with the two nails 1/4" apart and 1 nail wired to the block and a spark-plug lead on other. Got nothing. Should that homemade tester not have worked? I checked both leads and got nothing. Where do I start under the flywheel? It has red coils and points and condensers look fairly new.
 
Ok, I fibbed a little. I didn't ground to block, I had wrapped wire around end of spark-plug. I moved it to a unused,paint free, screw hole and got a weak, white spark from the bottom lead. Still nothing from the top lead.
 
Motor is running! The 7.5 had updated green coils, so I stole them. I'm getting a rather large shopping list for the 7.5. Have problems with water flow now. I've gotten so far off topic from the title, I'm going to start a new thread. Thanks all.
 
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