35 HP Johnson SeaHorse w/electric start...intermittant miss during throttle-up

[revolregita]

We have a 1981 35 hp Johnson SeaHorse w/electric start.... long shaft,<br />Problem: Starts perfectly, idles perfectly... but when you begin throttle up it misses intermittantly,<br /> it doesn't reach maximum RPM's, and the boat doesn't plane out. <br />Laura's description of the 'throttle-up-miss' sequence: "The motor runs smoothly in idle/low throttle<br />as we glide out into the bayou... then when Max opens the throttle it begins to start a sequence of<br />revving up and letting off...with a *grabbing* or seizure action and *clunk* at each let-off. And as Max says<br />it never reaches maximum RPM's or plane out." <br />We've taken the compression on both cylinders, both are good....<br />Replaced the spark plugs with new Champion plugs...<br />Replaced the tank hose, cleaned tanks(it has metal tanks), refilled with new gas...<br />Installed a rebuilt carbuerator which was pre-adjusted, (not sure if it is adjusted properly though)<br />The problem has been consistent despite all the above improvements/adjustments.<br />We would really appreciate any suggestions that would get us back to enjoying all the boating<br />and fishing we've been missing....<br /> tyia Laura (typing) and Max (dictating)

 

[jegervais]

Re: 35 HP Johnson SeaHorse w/electric start...intermittant miss during throttle-

Re: 35 HP Johnson SeaHorse w/electric start...intermittant miss during throttle-

Are y'all doing your own work on this?? Have you got the correct service manual?? If not, you NEED it, if you've got one, start with the sync & link adjustments. These adjustments set up all the linkages, so that the throttle and ignition timing advance at the correct time and the correct amount. You may have the carburetor throttle plate opening too little or possibly too much. If you have a timing light, you may also want to "index" the flywheel and check timing on both cylinders. To index the flywheel, bring #1 cylinder to TDC and make a white mark (#1) on the flywheel at the timing pointer. Repeat the process for #2 cylinder (marking it as #2). When you run the engine look for one cylinder and only one cylinder to fire at a time. If you see a "ghost" image of the other cylinders mark, that would indicate a double firing power pack.<br /><br />Before you go there, tell us more about this "clunk", is the engine acting like its coming out of gear (i.e. banging really hard)??<br /><br />-John

 

[revolregita]

Re: 35 HP Johnson SeaHorse w/electric start...intermittant miss during throttle-

Re: 35 HP Johnson SeaHorse w/electric start...intermittant miss during throttle-

^<br />Thanks for the reply John <br /><br />Found the info you sent in the wee hours. My father-in-law came to visit this afternoon, so he and Max put the first part of your info to use. <br /><br />I'm very pleased to report that so far the adjustment to the carbuerator has eliminated the miss {crossing fingers}... the true test will come this weekend when we set her into the water<br />and see whether the rest of the symptoms have changed. If not, then the next phase will be to utilize your next suggestion... as soon as the correct manual for our motor arrives, of course. If the problems are solved, than the next post will be the telling of a long awaited fishing trip, either on the river or down my beloved bayous. {our pond is just waaaay too small}<br /><br />About the 'clunk' noise..... as soon as we take her for a test 'drive' I'll write more about the clunk I heard (and felt as a jolt). <br /><br />What a wonderful way to end a day. <br /><br />Thanks again.... <br /><br />Laura & Max

 

[rwise]

Re: 35 HP Johnson SeaHorse w/electric start...intermittant miss during throttle-

Re: 35 HP Johnson SeaHorse w/electric start...intermittant miss during throttle-

Max and Laura <br />The "clunk" could be a problem in the lower unit. Sounds like the clutch dog is slipping. Ouch,,,<br /><br />Richard