Any ideas on 30 Hp Johnson (long)

[acreman]

Good Morning, <br /><br />This is my first post and it is a doozy. This is my dads motor and had set up a couple of years. Model number is J30TELCCE.<br /><br />The motor would crank and run but just not right so here is what I have done so far.<br /><br />Borrowed a Johnson service manual, bought a new hose and bulb (WalMart)and a new plastic tank. rebuilt the fuel pump and carb, replaced the plugs gapped to .040, ran a compression check(both in the 130's), replaced some hoses, and repaired the manual primer.<br /><br />Motor cranks easily and idles smoothly now and will run WOT (30mph on 14' Grumman) but when you ease the throttly back any at all it bogs and then will not take gas until you return to an idle. After that it will take off again. Pumping bulb has no effect on it. Just out of curiosity, bought a new fuel pump and tried it so I could rule out my rebuild job and no difference so I put the old one back on. When I rebuilt the carb. I noticed a small hairline crack on both sides of the emulsion tube. Dealer said it could not be replaced. I took the tube out with a bullet puller without damaging it and soldered it up. Looked good to me. <br /><br />Since motor still would not act right I ended up buying a new carb. Yesterday I put it on and it ran no better than the old one. One thing is that I had to use the old float chamber with the new carb per a tag on the carb. New carb had a 65D jet in it. I left my 70D in the old float chamber and put it on. <br /><br />I am out of any ideas and would welcome any help.<br /><br />Thanks,<br />Mark

 

[michligj]

Re: Any ideas on 30 Hp Johnson (long)

Mark,<br />did you do a sync & link after the carb rebuild?<br /><br />It sounds to me like you might be having some issues with your timing. <br /><br />Check to make sure that the timing advance mechanism operating properly and not sticking. Look up one of Joe Reeve's posts about sync & link for some helpful info.<br /><br />Good luck

 

[Walker]

Re: Any ideas on 30 Hp Johnson (long)

Did the Manual call for .040 sparkplug gap??<br />Sounds awful wide to me. How about trying .035 or even .032

 

[acreman]

Re: Any ideas on 30 Hp Johnson (long)

Thanks for the replies JM and Walker. <br /><br />I did do a link & sync but may not have it right on. I will check it some more today after work.<br /><br />Walker, the manual calls for .040 plug gap, but I did try smaller gap and couldn't tell much difference. <br /><br />I didn't mention in the original post that if I start from an idle and advance the throttle it will run at any speed. Only when backing off from wot does it bog down and will not pick back up until I go back to idle. <br /><br />Thanks,<br />Mark

 

[itstippy]

Re: Any ideas on 30 Hp Johnson (long)

Hmm. It could be some mechanical movement binding up. Take the hood off and put the motor in Forward. Slowly advance the throttle and watch the movement of the armeture, the wires, the throttle roller, the carb springs - everything that physically moves. Then slowly back off and look for anything that isn't moving back smoothly. Back all the way off - anything "snapping" back into place? Everything should move exacly the same as you back off as it did when you advanced - just in the opposite direction.<br />This advice is probably way off base, but you can't hurt anything by looking!