1984/85 Evinrude 70HP died while out on the lake

[Bikeluver43]

Hello all, its been a long time since I've posted mainly because my boat has been running very well for the past few years. Well she sat on the trailer for the entire season last summer with a few starts to make sure she was ok. I got fresh gas and oil, put a new battery (not needed but did for safe measure), and hit the key, like normal she fired right up. At first not all 3 cyl's were hitting but she coughed out of it. Off to the lake we went. Launched, took off and was driving for a good 15-20minutes mostly at cruising speed with full throttle only used to get up on plane. While on plane and cruising the motor started to die, sounding like it was out of gas which I new it wasn't. She stalled out, but started back up. Went to get going and she'd only run at slow speeds, anytime I'd try to give gas to get on plane she'd die back out almost sounding like I was flooding the engine. After a few restarts it would only start if I choked it (has the push in key choke) while I gave it throttle in nuetral.

Things I checked:
- Fuel level was fine.
- Nothing caught on prop
- Remove flame arrestor cover and nothing clogging the carbs
- Fuel line is not kinked
- Fuel tank line to motor is new last season as is the ball
- Fuel primer ball was hard, never lost pressure running or starting
- Plugs are probably a season old.

What I'm thinking may be wrong - Carbs may have gummed up from sitting. I used fuel stabilizer before last season but nothing over the winter into this season. - Motor may need to be decarbed with SeaFoam? Possibly a clogged fuel filter or the screen in the fuel pump as I cannot find a fuel filter in the motor anywhere.

Looking for help! Thanks

 

[Bikeluver43]

Re: 1984/85 Evinrude 70HP died while out on the lake

Sorry I also wanted to mention I run closer to 40:1 on mix, always have and never caused an issue. Just wanted to make sure I got everything out there for everyone.

 

[Will Bark]

Re: 1984/85 Evinrude 70HP died while out on the lake

Sounds like time to get the carb rebuild kits and make sure the hi-speed jets are really clean. Good luck

 

[Bikeluver43]

Re: 1984/85 Evinrude 70HP died while out on the lake

I was thinking the same thing. What has me confused is why it would run fine for so long then just randomely die out like that? Maybe some crud from the float made its way into the jet orifice?

 

[JDusza]

Re: 1984/85 Evinrude 70HP died while out on the lake

Two cents:
Remove the silencer cover and spray premix into each carburetor while running. This will identify the bad actor(s). If the carb is functioning, the spray will flood the cylinder and the engine will want to die. If the carb is starving, the spray will increase engine speed (rpm) and indicates fuel starvation at that carb.
Also, remove the fuel lines at the carburetors and spray carb/choke cleaner into the inlet valve. I've saved many carb tear downs this way. Might blow something out. Try to avoid the tear down.
J

 

[Bikeluver43]

Re: 1984/85 Evinrude 70HP died while out on the lake

Thank you I'll certainly give that a try. I'm really not wanting to "open" this motor or carbs up if I don't need to. If I do end up needing to rebuild the carbs, is it simply rebuilt, reattach the linkage, and start her back up? Or do these carbs need to be sync'd?

 

[Bikeluver43]

Re: 1984/85 Evinrude 70HP died while out on the lake

Ok, so last weekend I pulled the fuel lines and replaced them going to the carbs as they were cracked. I spray'd carb cleaner through the fuel inlet and gave the carbs a good cleaning at least from where the butterfly's open. I also opened the fuel pump and cleaned the screen and put it back together. I tossed some Seafoam in the tank and started it up. She ran excellent with no load so down to the lake I went. I dropped it in the water and she started up fine again but wouldn't rev very much and eventually died (all in neutral). I got it started again and had the lever full throttle to keep it going. It rev'd but not very much and stay'd at the same RPM the entire time. I walked to the engine and pumped the primer bulb, every time I did this the engine would finally start to Rev up the way it was supposed to. I'd only pump 2 or 3 times so the motor would rev up then eventually settle back to where it was.

This has me suspecting the fuel pump so I bought a rebuild kit from Iboats. For the $10 I figured it was time anyways. I also realized the engine is a 1982 not a 85.

Anybody agree/disagree?

 

[Bikeluver43]

Re: 1984/85 Evinrude 70HP died while out on the lake

Ok...

So I got the kit yesterday and realized it came with no diagram's or instructions. Is it pretty self explanatory as to what goes where (just reverse the disassembly) or can someone point me in the direction of a site that has it broken down?

It'd be greatly appreciated

 

[Bikeluver43]

Re: 1984/85 Evinrude 70HP died while out on the lake

Wow this forum really is dead, when I post on other forums there is a lot more activity and help offered.

Anyways, I plan on tackling this rebuild on Sunday or possibly Monday evening. I'll be taking a lot of pictures to show others who may stumble upon this thread, how to rebuild the fuel pump since every diagram I find online doesn't show how the gaskets are assembled.