1990 70 hp Evinrude VRO runs on two cylinders

[Gregb5220]

Hello, Im stumped on a problem with my outboard. Motor starts up and runs, but runs on two cylinders it sounds like. Starts up, idles a little rough, put it into gear and it dies unless i give it a little gas. Then it sounds like its on two cylinders. Changed the power pack, plug wires, and plugs. Did a compression test and got fairly even readings between 103-105 lbs on each cylinder. New fuel filter and water seperator installed as well as a new fuel tank over the winter and fresh gas. Problem came out of nowhere, two days before this started it was pushing my 17' center console to 31 mph. Always ran great at high and low speed. Ran solid last year and came from an owner who used a reliable mechanic I know personally. Any ideas would be greatly appreciated..thanks!

 

[EricJRW]

Re: 1990 70 hp Evinrude VRO runs on two cylinders

How are your fuel lines and carburetors?

Here's what I found in my carbueretor... Obviously crud* blocking the HS orifice is not good.



*In this case the crud was a non-standard, possibly "home made", gasket that decomposed and fell into the float bowl.

 

[boobie]

Re: 1990 70 hp Evinrude VRO runs on two cylinders

Did you check the spark on all the cyls with an open air gap spark tester set at 7/16 " ?? If that's okay, take the air silencer cover off, get a squirt can of premix fuel. Start up the mtr and squirt some fuel into each carb throat until you find the dead cyl.

 

[Gregb5220]

Re: 1990 70 hp Evinrude VRO runs on two cylinders

Thanks for all the help! Ended up taking the carburetors off and having them rebuilt..put them back, had the mechanic adjust the linkage, still the same problem! Fuel lines are clear..ignition coil maybe? I don't think there's anything else in the ignition system besides the timing, and from what I understand I need the boat to be out and unrestricted to do so and as soon as I drop the speed down a little in nuetral it dies! Stumped!

 

[phillnjack2]

Re: 1990 70 hp Evinrude VRO runs on two cylinders

Well i was getting same thing with my 1995 60hp vro.

It was running fine then seemed be a bit dead on a cylinder.

i took carbs apart cleaned them ,still same problem,
changed power pack, still same problem,
changed coils,still same problem.
even took the reed block down and looked at the reeds etc.still same problem.

turned out to be the fuel pump not pumping enough fuel, and also leaking air.


maybe yours is doing the same, try old style fuel pump with pre-mix to see what happens.

phill

 

[retiredfornow]

Re: 1990 70 hp Evinrude VRO runs on two cylinders

Do what boobie said, and if you find the dead cyl., switch the coils from a good cyl. and see what you get.

 

[Gregb5220]

Re: 1990 70 hp Evinrude VRO runs on two cylinders

Thanks! Turned out to be the top coil..by the time I got the carbs tuned right the isulation had worn away enough so I could see the spark coming thru!