1977 70hp Evinrude

[freedon]

So I dusted her off after sitting for two years, changed the gear oil, plugs and she fired up like she came off the line yesterday. Warmed it up to clear the smoke from the fogging and proceeded to go out to the channel and opened it up...there was a little hesitation (something I remember from before it was stored) but it smoothed out and the boat came up on plane...no worries.

Took a 10 minute ride down the channel cut her back and spun around to head home, opened her up again and stated home. Got about two minutes in and she cut out..COMPLETELY... almost throwing me over the windshield (I was enjoying this years first run on the water).

Tried to start it back up and nothing for about 5 minutes... then she fired up begrudgingly but as I eased the throttle forward cut out again.

I then fought with it to get going and eventually figured out that it needed full choke and lots of throttle to get going... once it was running I could manipulate the throttle up and down and it seemed to run great revving with no problems...but as soon as I put it into gear it wouldn't go past about 20% throttle before stalling again... I had to nurse it back into the dock and head home...

..some other things I tried...while she was running and in gear I pumped the bulb, no change
...took the cover off and watched the throttle linkage and everything looked normal
...checked the wires and everything looked tight
...checked the tank vent and connections and even switched to my second tank and no change.

I did noticed that the two little exhaust holes at the rear were not spitting any water...(I will admit that I bought the boat two years ago but only ran it a few times so I dont even know if water SHOULD be coming out of the holes...) not sure if overheating might be an issue...

The only thing i can think of is that it is a carb issue. I figure they could use rebuilding so I ordered the kits. Any thoughts????

Oh yeah, I remember reading on a post here that the factory jets on this motor were changed in a later year cause it had a tendency to run lean... could that be the issue (or a contributing factor)?

Any help/insight/suggestions are appreciated. I am very green with boats and just learning the ins and out of two strokes.

Many thanks!

 

[JimeeB]

Re: 1977 70hp Evinrude

Freedon.
I have the same motor only with a different problem. But to answer one of your questions YES water should be coming out of the exhaust ports. There will be more at higher rpm but should have a little at lower rpm. If not then drop the gearcase and replace your water pump (or at least the impeller). as for the rest of your problems these motors have been known to run on only 2 cylinders. check all your splugs and see if you see any evidence of this.

 

[Sixmark]

Re: 1977 70hp Evinrude

You have multiple possible scenarios, here are just 2:

1. You overheated it to the point that parts are starting to fail, usually electronics are the first to give up the ghost.

2. You had sediment and crud that was floating around in the carbs/fuel system and lodged itself into an area that you don't want it to be in.

 

[freedon]

Re: 1977 70hp Evinrude

Ok ok, thank you for the info fellas. Sort of confirmed what I suspected. So my course of action will be to clean and rebuild the carbs and the water pump (at least the impeller).

As for the spark plugs 1 and 2 were dry, a little black and smelled a little burnt (smelled like burnt oil).

# 3 was a little wet with fuel, black and had the same smell.

My first impression is that the color and smell are normal but that #3 might be the culprit either running too rich or not firing at all after the engine gets hot.

Gonna take a few days for the parts to come in but I will post more once I get the work done.

Thanks again!