A7s the final chapter

A7s the final chapter
Posted by NoSlack on Jan-19-04 at 05:10 PM

Today was a much better day than yesterday.
All I could think about at work this morning was getting the boat back together and seeing what the new prop were going to do for me. By 10 AM I couldn't take it anymore and headed home to put the last hose back on.

I putt in at Ski Beach today so I could do some speed run as close to the ramp as possible, just in case I had more problems and needed to limp back to the trailer.

I started out slow, keeping a close eye on the temp gauge. Just myself onboard, bait tank full, 90 gallons of fuel and all the rockcod lead I could find in the garage was today's test load.

1400 RPM 5.5 knots 160 degrees
1800 RPM 7.0 knots 160 degrees
2500 RPM 11.6 knots 165 degrees
3000 RPM 16.8 knots 165-170 degrees
3100 RPM 18.8 knots 170 degrees
3200 RPM 20.2 knots 170 degrees
3400 RPM 22.0 knots 175 degrees
3600 RPM 25.2 knots 175 degrees

The engine is still not loaded like it was with my old single prop, but I think I'll stay with the A7s through the summer and see what 67-70 water and a couple of overweight fishermen do to the engine loading.

I have basically picked up 2.5-3 knots and dropped the load on the engine by going to the Duo-Prop. I used to run 17 -18 knots at 3200 RPM with a coolant temp of 180-185 degrees.

Mike


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#1, RE: A7s the final chapter
Posted by moo fish on Jan-20-04 at 10:25 AM
In response to message #0

A couple of questions: Do you have any gph's (flowscan) for the different rpm's? How many hours on the grenaded impeller? Precharging the strainer makes sense. I have some extra lids and may experiment with adding some mechanism to add water to the strainer without removing the lid.....rt

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#2, RE: A7s the final chapter
Posted by NoSlack on Jan-20-04 at 06:03 PM
In response to message #1

I have no idea what my fuel economy is now or ever was at any given RPM. All I've ever checked is my average MPG per tank by seeing how many miles I go on a give amount of fuel.
As far as the hours on the impeller goes, how does 761 hours sound. I know that is way to long, and I was on borrowed time. I didn't record in the service book when I changed it last, so I had to go back and look at the date on the photos of the fish from the day. I remember the day well because I came back in at a reduced RPM(3000)do to temp concerns.

Mike