89 Johnson 70hp VRO looses rpm@WOT

[baldman]

My '89 Johnson 70hp VRO chops it's rpm down next to nothing after being at WOT for about a minute. I have to shut down, wait 3 minutes, and it's ready to go again. No warning horn. The horn is fully functional. Carbs have been rebuilt from the ground up, new stator, power pack, temp sensor, new fuel lines, oil lines, main wiring harness, etc. <br />Here's the kicker...If I sneak up to WOT slowly over time it runs all day!<br /><br />HELP!!!!!!

 

[paddleless]

Re: 89 Johnson 70hp VRO looses rpm@WOT

T Thats very ironic that I experienced the exact same problem with the same type of motor today ,I think mine is a 1992 though (sisters boat).I'm trying new plugs in the a.m. I'll let you know how it works out.

 

[baldman]

Re: 89 Johnson 70hp VRO looses rpm@WOT

I tried new plugs, didn't work. I've done just about everything to this motor, except look at the VRO itself. My gut tells me that for some reason, the VRO can't adjust as fast as I can throttle up, then the oil viscosity sensor takes over and chops the rpm.

 

[DJ]

Re: 89 Johnson 70hp VRO looses rpm@WOT

Thunderfish,<br /><br />Remove your oil injection tank and clean it out. Replace the pick up sock and reinstall.<br /><br />Purge the lines and give it a try.<br /><br />MAKE SURE to run pre mix (50:1) until you verify oil useage. Just put a mark on the side of the tank. You should see a noticeable drop in about six gallons of fuel useage.

 

[paddleless]

Re: 89 Johnson 70hp VRO looses rpm@WOT

I tried the new plugs today and it ran better but it seems that my fuel ball isn't staying full.I'm going to try a different hose and if that doesn't work I'll try the cleaning of the oil tank.I'll keep you posted thanks for the check-in.