Exhaust relief port on 1973 6hp Evinrude?

steviecops · #1 October 8th, 2004, 12:49 PM

Hi

I just got hold of an old 1973 Evinrude 6hp Fisherman. It's in a sorry state, but I'd love to get it running again.

There is a really bad repair that's been done where I think the exhaust relief port should be, (if it has one!). At the top end of the exhaust housing, someone has fixed a short tube, about an inch in diameter, coming out of the housing. They've fixed it there with glass fibre bandage that's wrapped around the housing! Any ideas what should be under there, and is there a better method for fixing whatever it is? I've got Seloc and Clymer manuals, but can't find what this tube thing is supposed to do.

Also, What would be a reasonable compression reading for this engine? I know that even compression is more important than numbers, but I just need a rough idea what it should be.

Thanks in advance.

Steve

BF · #2 October 8th, 2004, 01:17 PM

I've got a couple of 70's era 6hp's... I'm not sure if your '73 would be different from mine... but mine just have a single hole in the rear of the leg (1/2 way down). The only other exhaust exit point is behind the prop. If someone stuck a tube in the exhaust exit hole 1/2 down the leg, maybe it was to put the exhaust just below (or above) the surface of the water when trolling (??). I use mine as a trolling motor, and depending on the load of the boat, size of waves, and how the 70lb lab is moving around, the exhaust outlet can sometimes dip below the water line. This changes the backpressure, and affects the idle speed. If I'm really trolling slow, it could cause a stall... it's no biggie on my boat, but maybe on a different rig it'd be a pain.

Just my guess on what it might be about, if I read your description right... As for compression, I don't think these engines had particularly high or low compression.. So, I'd think a number of 100+ and even would be good. Less might be OK too. In my mind 80's or less would be low.

Good luck!

BF · #3 October 8th, 2004, 01:20 PM

I've got a couple of 70's era 6hp's... I'm not sure if your '73 would be different from mine... but mine just have a single hole in the rear of the leg (1/2 way down). The only other exhaust exit point is behind the prop. If someone stuck a tube in the exhaust exit hole 1/2 down the leg, maybe it was to put the exhaust just below (or above) the surface of the water when trolling (??). I use mine as a trolling motor, and depending on the load of the boat, size of waves, and how the 70lb lab is moving around, the exhaust outlet can sometimes dip below the water line. This changes the backpressure, and affects the idle speed. If I'm really trolling slow, it could cause a stall... it's no biggie on my boat, but maybe on a different rig it'd be a pain.

Just my guess on what it might be about, if I read your description right... As for compression, I don't think these engines had particularly high or low compression.. So, I'd think a number of 100+ and even would be good. Less might be OK too. In my mind 80's or less would be low.

Good luck!

steviecops · #4 October 8th, 2004, 02:26 PM

Thanks BF, the tube is about half way down the leg. As this motor is a longshaft, I suppose it is nearer the powerhead than the prop.

As the job is scruffy, I'll rip it out and look what's underneath. Maybe the hole was corroded or damaged in some way, or maybe it was something to do with what you said. Only one way to find out I suppose.

Thanks again.

Steve