6hp Evinrude troubles

[FishHog]

I have a 76' 6hp that I use up at the cottage. Its run like a top for years, despite my negelect to it. <br /><br />I brought it home at the end of the season to give it a well deserved once over. Replaced lower unit seals, cleaned the carb, new plugs. Everything looked great.<br /><br />took it up for deer season, and it would only run half throttle. If you put in in to neutral, it would rev up and sound like it was firing on both cylinders, but under load only sounded like it was firing on one.<br /><br />so, while running, I pulled the top plug wire off, and it didn't change anything, still running at half speed. Pull the bottom and it would die.<br /><br />I tilted it up, to get the prop out of the water some, and you could hear the top cylinder kick in and it would rev up. Lowered it back down and ran it for 1/2 hour at full speed with no problems. As soon as I slowed it down, you could hear the top cylinder quit firing.<br /><br />I figured it was electrical, but pulled the top plug to check for spark and it started up fine on the bottom cylinder and the plug in my hand appeared to be firing well.<br /><br />I'm sort of stumped. Guess I shouldn't have touched it.<br /><br />any suggestions of what the problem might be?<br /><br />thanks,<br /><br />FishHog

 

[JB]

Re: 6hp Evinrude troubles

Howdy, FH.<br /><br />Look for gasket leaks on the intake manifold, bent or broken reed for the top cyl, gasket problems with the bypass cover on the top.<br /><br />Good luck.

 

[fireman57]

Re: 6hp Evinrude troubles

Sounds like a bad powerpack. They will break down under a load and fire only at idle.

 

[G DANE]

Re: 6hp Evinrude troubles

A 76 6 HP unfortunetely has no powerpack. Did you wash the motor down or something similar ? The 76 6 HP has points and if you have hosed it down i. exa. , water might have gotten under flywheel and a set of pionts is dirty. First rig up some kind of spark gap, from wires to ground and check if both will jump a 5/16" gap with strong equal blue spark. Jumping in sparkplug in free air tells next to nothing. Put a nail in boot and hold it with an insulated plier 5/16 from ground, make someone else pull cord. If spark is fine, you probably messed something up in carb. Did you put the little centergasket around high-speed ventury in place, when you put floater bowl back on ?? Did you adjust floater hight correctly, or maybe bend floater, making hight too high ? If you did one of the last, it will flood at higher rpm.

 

[Vic.S]

Re: 6hp Evinrude troubles

Is it possible that one of the new plugs is faulty? Have you swapped them over to check?

 

[FishHog]

Re: 6hp Evinrude troubles

Vic, that just might be worth a try. Never even crossed my mind that a new plug wouldn't be OK, but I guess its possible.<br /><br />thanks for the tips G Dane, I'll check everything over again.<br /><br />FishHog

 

[FishHog]

Re: 6hp Evinrude troubles

Been a busy winter, and finally got some time to look at this. Actually bought a spark gap tester and found that I can't jump much of a gap on the top cylinder. It will spark with a small gap, but not much of one.<br /><br />bottom cylinder has a good strong spark.<br /><br />so, I'm going to check points/coils/condensers, but am not sure as to whether one set is for each cylinder or if the cylinders infact will share the spark for each point, depending on firing.<br /><br />OK, that didn't make sense. Let me try this. If I switched the points/coils/cond would my problem switch to the other cylinder?<br /><br />If so, then I should be able to switch one component at a time to determine what is actually faulty.<br /><br />thanks guys,<br /><br />FishHog

 

[JB]

Re: 6hp Evinrude troubles

Good plan, FishHog.<br /><br />There are two completely independent magnetos there. The only things they share are the cam and the flywheel.<br /><br />It's a tougher job to switch, but the coil could also be the villian.

 

[FishHog]

Re: 6hp Evinrude troubles

Great, thanks for confirming that JB.<br />I'll give that a try.<br /><br />FishHog

 

[Paul Moir]

Re: 6hp Evinrude troubles

Check the top crank seal when you have the flywheel off. If it's blown it'll hurl oil all over the points making both cyls' spark weak.<br />Also, if the engine has a kill switch then disconnect it and isolate the two wires that go to it. If healthy spark returns, it's probably full of water.