1996 Evinrude 70 hp - Trouble Shooting Help!

[Jaypo]

I have a 70 HP Evinrude on my boat that has run fantastic for me for the past 2 years, but started misbehaving at the end of last year. It starts instantly and runs beautifully when you get out of the hole, but that is where my problem lies. 3 out of 4 times, when I punch the throttle from idle, it chokes out and kills. I have treated the carbs with seafoam and changed plugs with no change. It never spits or burps, just kills down. Coincidentally, the kill switch tether no longer kills the engine when you pull it off the ignition and the motor starts fine with the tether removed from the ignition.

I am thinking my problem is electrical with the ignition assembly and not fuel based with carbs, but would love others opinions who are more knowledgable.

Thanks!

[New Yankee]

Jaypo - I think it's still in the carbs. Had a couple of OMC 70's in the past and had the same problem with one (although it was yrs older than yours). Had the carbs rebuilt and same problem - went back and the shop told me the factory jets run too lean in order to try to reduce fuel consumption (both mine were still gas hogs...). Said they could put in oversized jets but I'd go broke on the gas.

This could have been a raft of you know what, and simply a bad rebuild but I worked around the problem by flicking the electric choke just before hard throttle and she'd have enough richness to get out of the hole. And it always ran OK in the test tank - I guess not enough load to cause the problem.

Seems like your kill switch issue is simply in the plug - something has allowed the circut to complete itself when the plug is out. May be wrong (just ask my wife) but I wouldn't THINK the issues are connected.

[efgh]

I have johnson 70H.P., did the same thing, found out it wasn;t getting enough fuel for those 3 cyl to crank, how I foud this, just before you went from idle to full bore I squeezed the primer bulb to load the line with fuel, tore right out then, took it to repair shop and they fixed the fuel pump.no more problem.

[Jaypo]

Thanks for your replies! I'm planning on taking it in this spring to have it addressed, but you can rack up some major financial damage by going in blind and letting them trouble shoot at $80/hr.

Appreciate any other thoughts as well..

[Valv]

I would just go a little further and have carbs rebuilt, which means putting new gaskets, seals, etc. and cleaned up well.

If you have a lean condition on 1 or more cylinder, it might score a it or worse. A good tuneup will take care of it.

While it's there you can have water pump impeller replaced.

It's a little more $$ than you wanted, but the cost or replacing powerhead or motor will be at least 10 times more.

Number 1 cause of outboard motor problems is NOT using it enough, people think that if they use them just 2 or 3 times a year, it will be fine and won't need any maintenance.

The number 1 comment to a damage is: "it was running great last year, what happened..."