'56 Johnson 7.5, Carb and Gear Case Probs

'56 Johnson 7.5<br /><br />First off, earlier this spring I replaced all the seals on the lower unit. I checked the fluid last night and there is tons of water in there. When I did the reseal job I noticed the prop shaft has scoring on it. First question is could the scoring let the water in? Second question, is there any common mistake when replacing the seals/what the heck did I mess up on?<br /><br />Second problem, I just rebuilt the carb and ran it today. Idle is great (why I had to rebuild it in the first place), mid power is good, but now it doesn't rev up all the way. I adjusted the carb to gain the max rev's but it still doesn't go as fast as before the carb job. And yes, I did set the float height and all that fun stuff according to specs. Just for the info, I did do a tune up on the electrical system so I doubt it is that. Any ideas?<br /><br />Thanks guys. The carb problem isn't as frustrating as the lower unit. Carb was quick and easy to rebuilt, getting out all those little seals and O rings in the lower unit wasn't.

Re: '56 Johnson 7.5, Carb and Gear Case Probs

Mornin' Maverick.<br /><br />Best way to find the leak in the lower unit is to pressurize the lowe unit with air and stick it in water. Any leaks will be readily apparent. I modified a bicycle pump to do this. Only need about 5 to 10psi. I don't think speculating about which seal is leaking will help. Just got to find it and fix it.<br /><br />When you were running the engine, did you set the high speed needle first? If the high speed needle is open to far, high speed will not happen. If the adjustments do not help, make sure the packing nuts are snug and not sucking air. Make sure gas lines are secure and tight. During the rebuild, did you remove the core plugs and hose out the passages good with carb cleaner and then blow out with compressed air? Last resort will be to remove the carb and look for "junk" blocking fuel passages. Good Luck!

Re: '56 Johnson 7.5, Carb and Gear Case Probs

I actually set the low speed setting first so I could at least idle it, then it took it to WOT and made those adjustments, then back down to idle, then back up, then mid, well you get the idea.<br /><br />I think I'll tackle this lower unit problem first then I'll take it out on the lake again to see what I can do about the carb. Yes I did remove the plugs and clean through the passages. I did notice that the high speed control needle wanted to move on its own. It has always done that. I know this sounds awful but last year as a cheap fix I just taped the adjuster down with duct tape

Re: '56 Johnson 7.5, Carb and Gear Case Probs

The packing nuts need to be snug. Adjust them till you can feel some resistance when making needle adjustments. Don't have a parts book with me right now but, did you sync the throttle opening with the timeing? The manual should explain this procedure.

Re: '56 Johnson 7.5, Carb and Gear Case Probs

I highly doubt it is posible to adjust the carb/timing on this old motor. The carb opens by that little piece that rubs on the plate that the points, coils, and condensor mounts to (that sits under the flywheel, I can't think of the name). When turning the throttle, the plate moves (to advance) and the slide piece moves the throttle on the cam of the plate. I've looked and there is no way to adjust any of that. When I was on the lake yesterday I even removed the hood and played with the throttle position as much as I could with the 1/8" of free play in the linkages but that did not help. Its like the motor just doesn't have the same power as before the carb job.<br /><br />Whats the best way to tighten up that needle? I've tighten the nut as much as posible with no cure (and yes, there is the gasket in there).<br /><br />Thanks

Re: '56 Johnson 7.5, Carb and Gear Case Probs

Carb timing is adjusted by loosening the ramp the cam follower rests on and adjusting it in and out. You adjust it so the throttle plate *just* moves when the cam follower is centered on the mark.<br />I'm wondering about that carb adjustment - I've never had any trouble getting them snug by tightening up a little on the packing.

Re: '56 Johnson 7.5, Carb and Gear Case Probs

Might simply need more packing material - the old stuff can get pretty condensed with age. Lacking the fiber washer for packing, I've used cotton thread, greased, then wrapped around the needle valve with the packing nut loose up near the knob. Put a few wraps of the thread in a small bead right above the threads, then slide the packing nut down to hold it in place. The grease also helps hold it together until you can get it back in the carb.... <br />- Scott