Evinrude Ski Twin 33hp knock at mid RPM

[gwoloshyn]

Hi Folks,
I just took out my Evinrude Ski Twin 33hp model 33653D that I thought would be running good. Let me begin by saying that just about every component on this motor has been replaced. New fuel system and ignition system. The motor starts and idles fine, but when I bring up the RPMs it has an intermittent knock or kickback and does not run right. The knocks are a few seconds apart and do not seem to be random, but a systematic noise. My carburetor has been completely cleaned with the factory needles set at 1.5 turns out for low speed and 3/4 turns out for high speed.

Along with this knock is a loss of power through higher RPMs and I cannot get on plane. Could this be a dreaded timing issue/link and sync adjustment? No power, and a knock at higher RPMs are the problems I am having. Once again, it has all new ignition components (coils, condensors, points, spark plugs and wires), and fuel system (carb rebuild, new fuel pump and all new fuel lines). Any help appreciated.

 

[boobie]

Re: Evinrude Ski Twin 33hp knock at mid RPM

What's the compression on it ?? What's the g/c oil look like ?? To check the g/c oil look for only a slotted screw, NOT a phillips head screw.

 

[gwoloshyn]

Re: Evinrude Ski Twin 33hp knock at mid RPM

What's the compression on it ?? What's the g/c oil look like ?? To check the g/c oil look for only a slotted screw, NOT a phillips head screw.

Compression is 90 psi both cylinders. The gearcase oil is brand new along with new lower end rebuild kit. I forgot to add, after running for a while it will die out when going back to idle speed.

 

[boobie]

Re: Evinrude Ski Twin 33hp knock at mid RPM

When you say "knocks" is this like a knock in the p/h or is it like you turned the key on and off very quickly ??

 

[nwcove]

Re: Evinrude Ski Twin 33hp knock at mid RPM

sounds like its more of a "sneeze" than an internal engine issue, could be fuel delivery/carb , could be ignition. maybe post a video?

 

[gwoloshyn]

Re: Evinrude Ski Twin 33hp knock at mid RPM

sounds like its more of a "sneeze" than an internal engine issue, could be fuel delivery/carb , could be ignition. maybe post a video?

I suppose it is a sneeze and not a knock as in an internal engine problem. It's pretty violent though, it shakes the whole motor pretty good. Should I try looking at the link and sync setup on this motor? That would be related to an ignition problem. As for the carburetor, my cork float looked like it needed replacing, maybe smaller pieces of it have made their way into the high speed passage since I've cleaned it out.

Combined with the sneezing noise is a complete loss of top end power, as I've stated above. Full throttle and I cannot get on plane. Maybe this could help someone diagnose what might be the problem.

 

[nwcove]

Re: Evinrude Ski Twin 33hp knock at mid RPM

the carb overhaul should have included replacing the old cork float. a carb soak and rebuild is a must do thing, as well as a new impeller. compression numbers would also help.

 

[boobie]

Re: Evinrude Ski Twin 33hp knock at mid RPM

I still think it's an ign prob.

 

[gwoloshyn]

Re: Evinrude Ski Twin 33hp knock at mid RPM

the carb overhaul should have included replacing the old cork float. a carb soak and rebuild is a must do thing, as well as a new impeller. compression numbers would also help.

The kit did not include a new cork float, but I can buy one which I'm considering doing. However, as boobie said I also think it's an ignition issue. As I also said earlier, I gave compression numbers and did a full carb rebuild. The lower end also has new components. It's a mint motor! Just won't run right :facepalm:

 

[gogetter510]

Re: Evinrude Ski Twin 33hp knock at mid RPM

From what i can tell i was having a similar issue. I hadnt started the engine in years. put the rabbit ears on and fired right up. raised the throttle slightly above idle and asll was still well. i gave it a quick shot of throttle and it would kick violently. almost like sputter, but it was as if a single piston didnt fire. after idleing for about 5-10 minutes it would not longer act up. This is on a 1964 evinrude 40 big twin. i assumed it was ignition. i will look deeper into it. I will also keep an eye on this thread. good luck.

 

[gintstone]

Re: Evinrude Ski Twin 33hp knock at mid RPM

Seems like an ignition problem , kinda like what my motor would do (I got my '67 from some guy and had zero info on it, replacing water impeller was first, it broke all 6 veins into pieces). My motor would run great and then die down, run great, then die down, I pinpointed it to the lower cylinder having intermittent spark . I'v been trying to figure out what was going on with my '67 ski twin, don't quite have the money yet, but want to get on the water, so I'v been trying to diagnose exactly what was bad in my magneto by swapping parts around in there. After cleaning points and probing with the multimeter, I then tried swapping the coils and tried running the motor, still intermittent spark in the lower cylinder, then I swapped condensers and the intermittent spark moved to the upper cylinder. BINGO just needed a condenser. $5.30 here on iboats, j/k got it from my local dealer
Try pinpointing your ignition issue, if your in the same "boat" as me and a little low on cash. I went the cheap route, everyone says points condensers need to be replaced yearly, I let you know how far my $5.30 tune up gets me

 

[Big Jay]

Re: Evinrude Ski Twin 33hp knock at mid RPM

Did you ever solve your "sneezing" issue?

 

[kfa4303]

Re: Evinrude Ski Twin 33hp knock at mid RPM

Here's a great ignition tune up link. You can get a kit right here at iboats for aout $20. Be sure to use GRADE 8 bolts and washers on the flywheel puller as the stock bolts are not strong enough and may break, or strip the threads in the flywheel itself.

http://www.marineengine.com/parts/v...ntage-evinrude-johnson/278780/27878000001.htm



http://www.outboard-boat-motor-repa...on 3 HP 1952-1967 Ignition System Tune-up.htm

 

[djm0]

Re: Evinrude Ski Twin 33hp knock at mid RPM

I have the exact motor and the exact same problem. I'm attempting to get the fly wheel off to take a look but the puller I bought doesn't appear to have the right size bolts :S

 

[kfa4303]

Re: Evinrude Ski Twin 33hp knock at mid RPM

HI dj. You'll need 3 (1/4" x 20 x 3") Grade 8 bolts and washers/ You can find them at any Lowes/HD. Here's a pic of how the flywheel puller should be used.

 

[djm0]

Re: Evinrude Ski Twin 33hp knock at mid RPM

Hopefully I can find them at Home Depot here in Canada. Always a pain in the butt finding the right bolts... their sales guys suck lol. Thanks alot! This will save me a ton of time

 

[kfa4303]

Re: Evinrude Ski Twin 33hp knock at mid RPM

Hello again dj. I'm not sure how the stores are arranged in Canada, but you should be able to find the bolts in the large sets of drawers they have in the hardware section. Of course, you can really go to any hardware store. GRADE 8 is simply a measure of the bolts strength.

 

[HighTrim]

Re: Evinrude Ski Twin 33hp knock at mid RPM

djm you can also get them at Princess Auto. Stack some washers on there as well, with the Ski Twin the flywheels are on there good and will take some persistence to pop them off. Thread the nut back on loose before installing the puller to keep the flywheel from becoming airborne when she lets go. A little penetrating oil and heat on the taper may be necessary. I use an extension pipe on the handle for more torque. You may get reccomendations to use an impact gun on the puller bolt, but I would advise against that. Sometimes works well, but when things go wrong you get yourself into a whole lotta trouble. Lift up on the flywheel when rapping the center bolt when there is tension on the puller bolt. Be sure to thread the bolts in 7/16" exactly, no more, no less. Mark the threads with a sharpie if you dont get shoulder bolts.

Let us know how it goes.

 

[djm0]

Re: Evinrude Ski Twin 33hp knock at mid RPM

Worked like a charm! I grabbed the gear at Princess Auto as HD didn't have anything I needed. Lucky for me the Princess Auto is just down the street from my place

The coils look almost too new and the coil that seems to be firing the best is more beat up. I grabbed a tune up kit from my OMC dealer (points and condensers) and a feeler gauge to set them at 0.020. The points that were there looked okay but they were way off from a .020 more like a .0140 assuming I'm checking correctly. Here is what I'm doing: put it in gear, removed spark plugs, rotated prop to turn it to the highest point, insert feeler gauge, adjust screw, try again and tighten the screw back down measuring again for good measure.

 

[djm0]

Re: Evinrude Ski Twin 33hp knock at mid RPM

There is a little sponge included with the pin that holds the point arm in place. What/where does it go? There appears to be an old one in between a coil and the shaft just sitting loose?