18 hp ?

[duckbuster38401]

Re: 18 hp ?

ok i have put neew plugs rebuilt car, new points, condenser, and coils..still no power? what else could be wrong? is the boat just to big for the motor?

 

[Paul Moir]

Re: 18 hp ?

Is the bottom plug still getting wet? And not the top? Short out each plug wire in turn to ground to run the engine on one cylinder. See if one cylinder is producing any more power than the other. Are the sparks nice an healthy now?<br /><br />Does the primer bulb get hard when you pump it?

 

[duckbuster38401]

Re: 18 hp ?

i tried that the both are getting good spark...bottom cyl is 90 pounds top is 80 pounds...bottom is still a little more wet than the top...no bad...i have a 4.5 hp 70 model johnson that will push it almost as good..does the short shaft hurt it?

 

[duckbuster38401]

Re: 18 hp ?

does the older motors not run @ as high of an rpm @ full throttle as the new ones? it still sounds like it is not running @ full out put...w/ just a hose and clamp on the motor it revs up good...put it in the water it acts like it boggs it down?

 

[duckbuster38401]

Re: 18 hp ?

yes the primer gets hard it is a new tank and lines

 

[Paul Moir]

Re: 18 hp ?

No, that's the right shaft length for the boat. <br />That's a fair spread you have on the compression, but that may be due to extra oil in the bottom cylinder. The compression seems a little low but not serious.<br />This engine has a WOT range of 4000-5000rpms. Some new ones are 5000-6000 or so, but some are lower. The fact that the 4.5hp is doing as well as the 18hp points to a serious problem.<br />The reason I asked about the primer is I was thinking perhaps the fuel pump diaphram was leaking causing the cylinder it's hooked up to to run excessively rich. But if it's getting hard, then that's not the problem. One guy here recently filled up his engine with gasoline through a hole in the diaphram!<br /><br />Try disconnecting the two lines coming from the armature plate and isolate them. You'll have to choke the engine to stop it, but that'll isolate all the various saftey switches, etc.

 

[G DANE]

Re: 18 hp ?

Did you ever clean and adjust the carb ??<br />I think your carb has as well highspeed as lowspeed adjustable needle valve. Clean the carb throughtly, pay special attention to the small orifices just above throttle butterfly. Joe Reeves once posted following, about adjusting these carbs: Quote from Joe Reeves<br />The proper adjustment procedure follows:<br /><br />(Carburetor Adjustments - Two Adjustable N/Vs) <br />(J. Reeves)<br /><br />Initial settings are: Bottom high speed = seat gently, then open 1 turn out. Top slow speed = seat gently, then open 1-1/2 turns. <br /><br />Setting the high and low needle valves properly: <br /><br />NOTE: For engines that DO NOT have a shift selection, obviously there is no NEUTRAL position. Simply lower the rpms to the lowest setting to obtain the low speed needle valve adjustment.<br /><br />(High Speed) Start engine (it will run pretty rough), shift into forward gear, take up to full throttle. In segments of 1/8 turn, waiting for the engine to respond between turns, start turning in the bottom high speed needle valve. You'll reach a point whereas the engine will either start to die out or spit back (sounds like a mild backfire). At that point, back out the needle valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest setting. <br /><br />(Low Speed) Slow the engine down to where it just stays running. Shift into neutral. Again in segments of 1/8 turns, start to turn the top needle valve in. Wait a few seconds for the engine to respond. As you turn the valve in, the rpms will increase. Lower the rpms again to where the engine will just stay running. Eventually you'll hit the point where the engine wants to die out or it will spit back. Again, at that point, back out the valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest slow speed setting. <br /><br />When you have finished the above adjustments, you will have no reason to move them again unless the carburetor fouls/gums up from sitting, in which case you would be required to remove, clean, and rebuild the carburetor anyway.