33hp skitwin, intermittent miss

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FrankR
Posts: 3769
Joined: Tue Mar 10, 2015 6:32 pm
Location: Florida

Re: 33hp skitwin, intermittent miss

Postby FrankR » Fri Sep 14, 2018 9:11 pm

If it is doing it in neutral, it ain't the clutch dog.

vtfireman85
Posts: 29
Joined: Tue Aug 14, 2018 12:31 pm

Re: 33hp skitwin, intermittent miss

Postby vtfireman85 » Fri Sep 14, 2018 10:38 pm

FrankR wrote:If it is doing it in neutral, it ain't the clutch dog.

being the maiden voyage it is possible its 2 different issues, it could be the low speed jet too lean, I've been fighting with that too, today was the first round out with this boat, and the carb has just been gone through so I didn't have anything "set" it could be that it was chugging lean, however it does seem like its missing as intermittently at idle in neutral as it is wide open in gear and also at half throttle. I'm inclined to think its an ignition issue, as opposed to fuel as its so intermittent and sudden, I am on the lake this weekend and cannot dive into it too deeply, I am heading to a salvage yard tomorrow to get a set of controls as the FNR lever snapped off in my hand today. I had a 58 duratec with a 67 18hp evinrude for years and apart from general maintenance never had issues with it. this lonestar has been plagued with issues. thats what its all about I guess. Ive got to find a test wheel so I can really check it at home. its a long way to a lake.

bobw
Posts: 270
Joined: Sun Jan 22, 2017 8:21 pm

Re: 33hp skitwin, intermittent miss

Postby bobw » Fri Sep 14, 2018 11:22 pm

As Frank noted, if it's missing in neutral it's not the clutch dog. If it has a miss at virtually any speed, I'd still lean toward an ignition problem and I'd start with the old plug wires. Also could be a bad connection at the plug wire terminals, at either the plug or coil end.
Bob
AOMCI Member

1954 Johnson CD-11
1958 Johnson QD-19
1972 Evinrude 25202

Jerry Ahrens
Posts: 1075
Joined: Tue Mar 10, 2015 9:49 pm
Location: Lake of the Ozarks Mo.

Re: 33hp skitwin, intermittent miss

Postby Jerry Ahrens » Sat Sep 15, 2018 5:37 am

Here's something that came back to bite me after a recent ignition system rebuild on a Big Twin... The new coils I used did not have a threaded pin where the spark plug wire connects (screws) to the coil. After all these years, they now just have a straight ''pin'' that you simply push the spark plug wire on to. In turn, you really have to make sure the metal hold down clip on bottom of mag plate) is holding the wire from backing out. Make sure the little rubber boot is also in place. The other classic mistake, is the routing of the coil wires that go to the points (along with the condenser wires). They can easily get chaffed by the rotating flywheel. The modern coils have longer wires, so it's easy to do.
I rarely ever change plug wires. The 50s style wires are about bullet proof, and better than anything you can buy today. Cut in to an old one someday and see how their made.
Jerry Ahrens AOMCI Member MAPS Chapter President

lindy46
Posts: 243
Joined: Tue Aug 04, 2015 8:30 am
Location: Tennessee

Re: 33hp skitwin, intermittent miss

Postby lindy46 » Sat Sep 15, 2018 9:52 am

Did you clean the new points? They need cleaning too!

vtfireman85
Posts: 29
Joined: Tue Aug 14, 2018 12:31 pm

Re: 33hp skitwin, intermittent miss

Postby vtfireman85 » Sat Sep 15, 2018 12:10 pm

Cleaned new points, it does it at li rpm as well but seems to do it much less. It’s really quite violent when it does it wide open. I’m on the lake all weekend and don’t have the ability to pull the flywheel. Having problems idling low enough to shift when approaching the dock so I have to look int that. It’s time
I think to re-do wires and pull the carb again.

FrankR
Posts: 3769
Joined: Tue Mar 10, 2015 6:32 pm
Location: Florida

Re: 33hp skitwin, intermittent miss

Postby FrankR » Sat Sep 15, 2018 12:38 pm

I think you have two problems going on there.

That violent kicking at speed is the clutch dog. It is coming out of gear, rotating half a revolution and slamming back in gear. It feels like you ran over something when it does that, and does it over and over again. The worse the wear, the more often it does it. Eventually, it will beat itself to death if you don't fix it.

The slow speed (or in neutral) "miss" more than likely is what we call a "lean sneeze". Giving the slow speed knob on the carburetor a tweak to the left will often times cure that.

vtfireman85
Posts: 29
Joined: Tue Aug 14, 2018 12:31 pm

Re: 33hp skitwin, intermittent miss

Postby vtfireman85 » Sat Sep 15, 2018 2:16 pm

FrankR wrote:I think you have two problems going on there.

That violent kicking at speed is the clutch dog. It is coming out of gear, rotating half a revolution and slamming back in gear. It feels like you ran over something when it does that, and does it over and over again. The worse the wear, the more often it does it. Eventually, it will beat itself to death if you don't fix it.

The slow speed (or in neutral) "miss" more than likely is what we call a "lean sneeze". Giving the slow speed knob on the carburetor a tweak to the left will often times cure that.

its what I am wondering, clutch dog will be easy to diagnose and fix once I am out of the water, the other I wondered if it was also too lean, this engine is quite tight so I know its not leaning out around the crank shaft. id really like a prop wheel so I can try to diagnose this at home. I have also wondered if I am out of adjustment on the shifter, I am going to go look into that now. I would absolutely describe the high end issue as feeling like I ran over something and here in Squam lake, thats always a possibility. when god got done making lakes he put the extra boulders here, so it is especially alarming

fleetwin
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Location: Rhode Island

Re: 33hp skitwin, intermittent miss

Postby fleetwin » Sun Sep 16, 2018 4:57 pm

vtfireman85 wrote:ill have to open it up when I get home to check on that

Please don't rip the gearcase apart based on our "guess". Needless to say, we are not there, can not hear the motor misbehave, so are at a disadvantage for sure... Disassembling that gearcase is a big job, would hate to have you rip it all apart only to discover the clutch dog is not the issue....
Maybe you can post of video of the engine while it is misbehaving...

vtfireman85
Posts: 29
Joined: Tue Aug 14, 2018 12:31 pm

Re: 33hp skitwin, intermittent miss

Postby vtfireman85 » Sun Sep 16, 2018 5:57 pm

fleetwin wrote:
vtfireman85 wrote:ill have to open it up when I get home to check on that

Please don't rip the gearcase apart based on our "guess". Needless to say, we are not there, can not hear the motor misbehave, so are at a disadvantage for sure... Disassembling that gearcase is a big job, would hate to have you rip it all apart only to discover the clutch dog is not the issue....
Maybe you can post of video of the engine while it is misbehaving...

It’s gotten more frequent, the faster I go the more often, the clutch dog makes sense and I’ve had them apart before, doesn’t really bother me to do. I’ll drain the oil out and see what kind of shape the oil is in in any case. If it’s chunky that’ll be a good indicator. Frankly I find chasing intermittent electrical issues more frustrating than dismantling the gearbox to rule out an issue


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