New 650 in WRAIII dies over half-throttle

[perserd]

I'm in the 3rd stage of break-in (up to 90% throttle). I was able to, at 90%, plane the ski and had more power than original (bad) engine had when it did run.

But then, ski began to shake and vibrate a lot and great loss of propulsion occurred and sounded like I lost main bearing or something. To be clear, my RPMs were not affected (yet - see below), but rather it was a loss of propulsion; it was as if I lost my impellar (prop?), driveshaft, etc.

Then, I had propulsion back but only able to accelerate to 50% throttle - no more. Any past 50% and ski died as if it were being given too much fuel.

This is reminiscent of original engine, which had only one good cyclinder. Or perhaps my temp sensor is either malfunctioning and only allowing one cyclinder to fire, or it is working properly and I was overheating and it was only allowing one cyclinder to fire.

I will check compression in both cyclinders tomorrow; but until then, any thoughts?

[james donald]

Re: New 650 in WRAIII dies over half-throttle

may be high speed side of carb it may run ok on low rpm until engine needs more fuel for higher revs thats when you are not getting fuel from high speed jet side of carb

[Technical Support]

Re: New 650 in WRAIII dies over half-throttle

You have pump damage - see the tech article for inspecting it.

[perserd]

Re: New 650 in WRAIII dies over half-throttle

Perhaps I misdescribed what happened. By removing the direction nozzle, the outer exit nozzel, ride plate and intake grate, I inspected the impellar and wear plate as indicated. I didn't see any major issues, so I reassembled and took it for another spin.

I got to about same area on water, hence same amount of operating time, and it began to falter again. I could not go over 50% without dying and RPMs faltering greatly. I think I was mistaken yesterday when I wrote that my RPMs stayed steady and that it was only propulsion I lost. Today it did the same thing as yesterday without the vibration issue. Today, it felt as though I wasn't getting enough fuel and that it was sputtering a lot when I tried to increase to or beyond 50% throttle.

So, with tools I took with me, I turned it off and removed the temp sensor to see if that made a difference. It did. With the temp sensor off, I was able to increase to 90% throttle, plane out, and went about 50 or so yards - it ran ok, but with some intermitten non-rythmic sputtering. Then I quickly stopped it and reattached the temp sensor and started it again. It then ran basically the same way, with the sputtering, etc.

So, I thought perhaps it is the sitting for five min or so that is allowing it to cool down and run the same. So I sat for five or so minutes, started it up and it ran all the way back to my dock OK, on plane at 90% and varying throttle (with temp sensor in).

Thoughts?

[Technical Support]

Re: New 650 in WRAIII dies over half-throttle

Replace your sensor.

[perserd]

Re: New 650 in WRAIII dies over half-throttle

This morning, I took both out - still on first tank of fuel and in 3rd stage of break-in. Immediatly, the one with problems was not able to go past 50% throttle without dying. It would put and sputter and I had to granny-up the throttle, within the first 5-10 minutes of operation it began to go faster and was actually able to plane out, although it continued to put and sputter intermittenly and non-rhythmically.

I was able to ride, with the sputtering, etc., for about 1/2 hour or so, then turned 'round to head back to dock. At one point, I got to bridge with no-wake zone and idled/just a little throttle through it. When I got to where I could resume speed, I could not, again, go over 40-50% throttle without dying. I tried to granny it up, but it would not work. I turned it off, sat for less than 60 seconds, started it up again and was able to granny it up and vary the throttle once on plane all the way back to dock.

Thoughts?

[Technical Support]

Re: New 650 in WRAIII dies over half-throttle

First of all, stop running it while it has problems. Why would you risk damage by continuing to run it without making repairs? Second, as I said replace your sensor. Obviously it has a problem if you took it off and it ran correctly. After that I would look to the carbs.