90 hp Evinrude loses then regains power.

runningwater · #1 July 13th, 2007, 12:37 AM

I'm new to the forum. My 1994 90 hp Evinrude starts well and runs well at low rpms. At higher rpms the engine will intermittently lose power without stopping and then after about a half a minute or so regain power. The same thing happened last year and finally the engine would not start. The VRO2 was replaced and engine tuned, which cured the problem. Could the new VRO2 be shot after a year?

SawBum · #2 July 13th, 2007, 01:31 AM

Welcome!!!!!!! I have had a very simulare problem witha 1994 120hp Evinrude, all the guy's tried to help and for the most part, they did. Just one factor was over looked and never brought up. I was having fit's over this issue, went thru a lot of extra work and I am hoping I figured it out today. The impulse tube from the crankcase to the fuel pump is metered by a "impulse limiter" fitting. IF this fitting is clogged with carbon (which I have not pulled mine yet but explains all my poblems) it will not send enough impulse (vacume/pressure) to the fuel/VRO pump to operate it properly at higher RPM. This has drove me crazy and I am hoping this is my problem and I hope this helps you, if your impulse line is connected to a fitting on your crankcase that has a blue colored ring around it, remove it, clean it from any carbon deposits and or replace it. I am getting ready to do the same, if it fixes it, I will post it or if you want, I will send a PM. I have sveral posts under my name, SawBum, ck them out and see if our problems are close.

emdsapmgr · #3 July 13th, 2007, 06:29 AM

We have recently warrantied a new VRO pump for a customer. He's gotten two replacements for failed new pumps from Bombardier in the past year. Sounds like a fuel starvation issue. Your engine is consuming more fuel than the pump is delivering. Try squeezing the primer bulb and see if the engine stops surging. Also possible you have a fuel restriction, like a bad fuel pickup or restricted anti-siphon valve.

runningwater · #4 July 13th, 2007, 01:43 PM

Thanks for the input SawBum and emdsapmgr. I'm pretty religious about the quality of my gas - I have a fuel filter/water separator on the feed to the engine and I change filters each year (I removed the motors inline filter). Good to know the VRO may be under warranty, but I'll check the impulse fitting before taking it back to the repair shop.