1982 35hp evinrude hiccups at wot

[cchinchak]

Hello
I just bought a 35hp evinrude that only ran while the choke was on. I took the carb off and soaked for 4 hrs in cleaner and then blew out everythng with compressed air. I also changed all the fuel lines on the motor. I took the boat out and it ran great up until i got it to just over half throttle. the motor began to hiccup every 6 to 8 seconds but would keep running. At wot throttle the motor would hiccup every 3-5 seconds but keep running. Compression at 119 and 118 for each cylinder. The boat was going about 22 mph at wot pushing a 14 ft alumacaraft that weighs about 500 lbs. Any ideas what may be causing the motor to hiccup at higher speads??
Thanks,
Chris

 

[wilde1j]

Re: 1982 35hp evinrude hiccups at wot

It's running too lean and will fry a piston if not corrected. Lots of possible causes, such as air leakage into crankcase, crap in a carb, etc, etc. An OEM shop manual would be very helpful in troubleshooting.

 

[F_R]

Re: 1982 35hp evinrude hiccups at wot

Not. It is jumping out of gear, rotating 1/2 turn and slamming back into gear. People usually describe it as feeling like they hit a log or stump (or gator, here in the swamps). Cause is a worn out clutch dog in the lower unit. It will get worse. It is wise to fix it now before it beats the shift linkage apart also.

 

[cchinchak]

Re: 1982 35hp evinrude hiccups at wot

It doesn't feel like I hit a log and doesnt slow the boat down, but when it happens yiou can definitely feel it. The motor will jerk a bit each time it happens. Do you know the cost of repairing a clutch dog and is it something I can do myself? Could it be a synchronization issue?

Thanks,
Chris

 

[F_R]

Re: 1982 35hp evinrude hiccups at wot

Could I be mistaken? Yes, of course I can make mistakes. But I can tell you that after 24 years as a full time Evinrude dealer mechanic, your symptoms are classic.

No, it won't slow the boat down. At least it won't till it gets considerably worse.

Part number 319565 clutch dog is $82.95
Part number 388125 forward gear is $151.37
+ misc seals, oil etc
+ around $200 labor in most shops.
Expensive repair? Yes. But how much is a new motor?
Can you do it yourself? I don't know, how comfortable are you with the idea of tearing the lower unit completely apart?
You could get lucky and not need the gear, but most likely you will. They both wear where they contact each other and it is foolish to put a new dog against a worn gear. It won't last long.

 

[wilde1j]

Re: 1982 35hp evinrude hiccups at wot

F_R, I'm sure you're right after reading "hiccup". You're also very right about replacing both the dog and fwd gear. Someone here was suggesting reshaping the dog with a Dremel ... don't think that fix is long for this world, since the surfaces need to be hardened.

The real confirming symptom is the frequency of the "hiccups" increases gradually over time.

I should have known better, since I've rebuilt a large number of LU's with the same complaint.

 

[cchinchak]

Re: 1982 35hp evinrude hiccups at wot

F_R and wilde1j - Wow, I'm really bummed out about this. I did not expect all of this when I bought the motor. Before I take it in for repair, is it possible that I didnt get the carb cleaned well enough causing this to happen? The carb was extremely dirty/gunky when I took it off to clean. Wilde1j mentioned that it may be running too lean or sucking air...how would I check this out or should I even bother? When the motor does the hiccup it will also sputter very slightly. Is this a symptom of a bad clutch dog/fwd gear? I am hoping for an easy fix. I appreciate all of your help guys.

Thanks,
Chris

 

[wilde1j]

Re: 1982 35hp evinrude hiccups at wot

A decent OB mechanic will be able to tell very quickly if it's a LU problem or not. Jumping in and out of gear is very distinctive.

 

[cchinchak]

Re: 1982 35hp evinrude hiccups at wot

Wilde1j and FR
I forgot to mention that I had to put on a new shift control cable. If this is not adjusted correctly, is it possible that this could be causing the hiccup problem at higher speeds?
Thanks again

Chris

 

[wilde1j]

Re: 1982 35hp evinrude hiccups at wot

Sure, if its not letting the clutch dog fully engage fwd gear. You can test this by disconnecting the shift cable at the motor and manually shifting into fwd and then running at speed to see if the hiccups are still there. BTW, did the condition exist before the cable change?

 

[cchinchak]

Re: 1982 35hp evinrude hiccups at wot

I did not run the motor with the old cable...the plastic was cracked and the metal was rusty and spokes broken... so I don't know if it existed or not before putting on the new cable...I will call the previous owner to see if he remembers. If that turns out to be the problem, do I tighten up the trunnion nut so the manual shift lever is tighter towards forward gear?
Thanks,
Chris

 

[F_R]

Re: 1982 35hp evinrude hiccups at wot

That's the general idea. I prefer to put in forward manually with the cable disconnected, then adjust the trunion till the pin "fits" the shift lever and holds it snugly. If you overdo it, you won't have neutral or reverse like you should. Keep in mind that if the dog is jumping as we suspect it is, the cable can't prevent it from happening.

I suggest you take the boat for a spin with somebody else driving and you see if you can hold the shift in forward when it skips. If it is the dog that's doing it, you will definatly feel it in the handle when it jumps. When it gets bad enough, you won't be able to hold it in without unreasonable pressure, so don't try. That will accelerate the wear on the linkage and you will have twice as much to fix.

 

[wilde1j]

Re: 1982 35hp evinrude hiccups at wot

A new cable always must be adjusted. A shop manual, available thru this site, will give the whole procedure.

 

[cchinchak]

Re: 1982 35hp evinrude hiccups at wot

F_R
When adjusting the cable, do I need to have both the control box handle at wot as well as the lever on the motor or just keep the control box in neutral? Also, I ordered a manual today but won't have it for a week or so. Trying to get it operational by the weekend.
thanks
Chris

 

[wilde1j]

Re: 1982 35hp evinrude hiccups at wot

Box should be in whatever you're checking, i.e. neutral, fwd, rev

 

[cchinchak]

Re: 1982 35hp evinrude hiccups at wot

Just wanted to give you guys some feedback on what I found out. I had my wife drive the boat a WOT while I held down the shift lever on the motor and the motor ran smooth with no "hiccups". I tightened down the shift cable to where it runs in forward just fine, but, as you said may happen, I do not have reverse. Nuetral is there but not quite where it should be. I have to go back past the nuetral point and then forward to nuetral. So it looks like I have some lower end work to do. Thanks for all the advice in trouble shooting the problem.

Chris

 

[Captain Caveman]

Re: 1982 35hp evinrude hiccups at wot

Not meaning to hijack cchinchak's post, but I guess you've all diagnosed a problem creeping up in my 35hp 1979 Evinrude. A couple of times last year and then this past weekend, while getting on the gas to get up on plane it feels like the motor is hitting a log. Afterwards the gear lever was between forward and neutral.

I never have problems while running at any speed (WOT or trolling) but only when accelerating. I'm assuming that it's the clutch dog so at least now I know what needs some fixing. Luckily I think that I'm in the early stages of failure.

Thanks all!