1963 40 hp jonhson not getting to wide open throttle

[Lake time]

I hav 1963 that won't reach wot it's getting spark to both cylinders I put a new float in the carb compression is outstanding new points coils and condeners she just not reaching the full rpms it's on 14 foot mfg niagra it gets me moving about 10 mph pr plain that's it it's got a 12 pitch prop shouldn't it be doing a lot faster on the water

 

[bonz_d]

I would think that it would be able to reach plane and speed w/o out too much trouble. If you are not reaching operating RPM there is another problem other than the engine, providing the engine is in the condition you say it is and is running well. The prop you have should also be pretty correct for that set up.

Check that hull weight and try and determine if it's water logged. If not go back to the engine and restart trouble shooting. 1st check that the carb is openning all the way, then check that it's getting good spark to both cylinders under load.

 

[Lake time]

Yeah I recently got the boat it's been sitting for 10 year's I did everything you've supposed to to t motor everything except an engine rebuild all new ignition carb re build fuel pump all new lines I can't get under the floor to the hull if it is water logged how do I find out I know she has two plug one for above the floor and one for under it the carb and the armature plat are fully advancing to wot but it's only acting like I'm running it 1/4 throttle I have primed the ball at wot butt no change

 

[bonz_d]

To me the engine sounds as if it should be right. Couple ways to check hull, take it to a scale or drill a small test hole in the rear bart of the decking and see what comes out. Shavings should be dry

 

[racerone]

Find somebody with a " test propeller " and run the motor.----For you that is the quick and best way to find out if there is something wrong with the motor or whether it is the boat.------An experienced shop will not have difficulty with this problem.

 

[bonz_d]

racer, I know what a test prop is but am unfamiliar with the test it self. Is this done with the boat anf engine in the water or the engine in a test tank? Could you explain the procedure?

 

[racerone]

On the boat in the water , or the motor in an adequate size test tank----Something in the order of 500 / 600 gallons.

 

[F_R]

The symptoms cry out it is running on one cylinder. Before you go off looking for anything else, verify it actually is running on both. I'll place my money on it is not.

 

[Lake time]

Ok I took her out for a bit to day it's running on one cylinder but here is the issue I replaced the coil points condeners and spark wire in that cylinder twice now the symptoms have yet to change I'm stamped I did a cylinder drop test at wot and she shut down spark plugs gaped to .025 points .020 bottom cylinder running like a champ top not so much

 

[racerone]

What does a compression test say about the condition of the motor ?---Have you checked the reed valves ?

 

[Lake time]

Compression is 110 and 112 the reeds look Ok I don't completely understand there functions or how they work when I rebuild the carb I looked in their the ampere to be fine

 

[F_R]

Getting water into that non-firing cylinder? Of course that is an educated guess. The first thing you have to do now, is a spark test on that missing cylinder. while running. Should show a reliable, strong 1/4" spark. You need to narrow it down to spark or something else. BTW, .025" on the plugs is a tad close. And don't ignore the simple possibility you could have a bad plug.

 

[Lake time]

I think I figured it out the little green wire coming from the coil to the points was pinched between the coil and the mount I'm going to the lake after work tomorrow keep ya all poted

 

[Lake time]

One more question the gene on the motor doses that charge the battery or just hold the prop in gear I noticed when it's running I disconnect the battery it doesn't stay in gear is that normal but with the battery hooked up it stays in gear

 

[racerone]

The electromagnet for shift require constant 12 volts to stay engaged.---Did you check generator fuse ?---Did you polarize the generator ?

 

[Lake time]

Fuse is good what do you mean polarized the generator

 

[F_R]

One more question the gene on the motor doses that charge the battery or just hold the prop in gear I noticed when it's running I disconnect the battery it doesn't stay in gear is that normal but with the battery hooked up it stays in gear

The battery supplies voltage that does the shifting and holds it in gear. Obviously, if you disconnect the battery, no voltage, no go. The generator recharges the battery. If it were not recharged, it would eventually run down and you would have no shift or starter.

That is a DC generator. It does not charge at all until you get up around 2000 RPM, then it cuts in and supplies up to a regulated 10 amps to recharge the battery and supply all your other electrical needs.

Us guys that understand the old DC generators are getting old. Better learn from us now, before it's too late.

 

[Lake time]

So once the motor gets to about 2000 rpm the generator takes over on the electronic shift and charges the battery too is there a way to check that

 

[racerone]

Did the motor / boat not come with an ampere meter ?-------------Check battery voltage once it is running at full throttle.-------Should read ~ 14 volts.

 

[Lake time]

Yeah it did but does not work anymore Ok I'll give it a try