TOPIC: Trial run for my Merc 65

I finally got my little Glasspar up to the lake for a test run. The 64 merc 650 started and ran OK but took a really long time to get planed out, whether it was with one or two people aboard. Had to keep it at full throttle to keep on plane. Also the rpms sounded sort of low at WOT. Top speed was 24 mph (GPS). Guess I'll need to get a lower pitch prop. Many thanks to Joe Poole and all the folks here who have offered suggestions and advice about the prop.

s95.photobucket.com/albums/l144/nhcarter1/1959%20Glasspar%20Delmar/?action=view¤t=trialrun.mp4

s95.photobucket.com/albums/l144/nhcarter1/1959%20Glasspar%20Delmar/?action=view¤t=trialrun2.mp4

Looks good and sounds good. Nice to see it running on the water. Skip.

Looks good on the water! It's not winding out, though, and I agree the prop pitch is probably too large.

You might try moving the tilt pin out one hole, that'll pick the bow up a bit and may increase speed. She's riding pretty low in the water, all that wetted surface will really slow you down.

What pitch prop are you currently using?

HTH........ed

After having a closer look at your vids, I goota agree with ED. It looks like your motor is tucked in pretty tight to your transom. Move it out one or two hole and see where it runs at then. Also, were is your cavatation plate sitting at. Is it level with the bottom of your boat? If it is below you may want to raise it abit. From your vid of the motor running it is kinda hard to see where it sits.

I agree with Ed as well, lower the prop pitch and tilt the engine out one or two holes. It sounds like its only turning around 4000 rpm. Glad you got it in the water.

We tried moving the tilt out early in the day when the motor wasn't running real great, and all she would do was get the bow up high and wouldn't plane. We had a full tank of fuel, over 400 lbs of people, and a fairly large cooler aboard. Later, I set the tilt back to #1, removed the cooler and my son from the boat, and that's the first time she planed. The video was with my son at the helm. He's a big guy, weighs 240 or so. Once we got the motor cleared out a bit, we found she would then plane with a full load, but it took everything she had to stay on plane at 23 mph.

My next step will have to be a prop change, as well as freshening up the carbs and the fuel pumps. Then I'll experiment some more with the tilt. The cavitation plate is right in line with the bottom of the transom. The prop is a 17 pitch.

I'm sure I'll have some questions when it's carb time. I've done a lot of carb work over the years, not afraid of the things, but on this motor they're a little inaccessible. Looks like the starter, rectifier and some other stuff will need to come off first. I do appreciate all the help.

try a 13" pitch to start.

17 pitch but what dia.? I was caught out here when I first got mine. The 650 shared the large l/u with the L6's so L6 props will fit. There was a a smaller dia 17p prop just for the 650 & it makes a world of difference. If I run a 'normal' (I can't recall the diameters) 17p on my 65 it only runs up to about 4500, put the smaller dia 'correct' prop on & it pulls up to 5300. The props don't look that different but it makes a huge difference in performance. I am currently running a cupped L6 dia prop on her at the mo but it is a 14p & it still doesn't rev quite as high as the 'correct' 17p.


Geoff UK

I've got a 2-blade 15-inch aluminum available, prop #48-31074A2-15. It was rebuilt a few years ago and has been sitting on the shelf since... PM me if interested...

A 17 inch, make no wonder it won't run up for you! Way too much pitch for that boat, even a 15 may be too much. Drop the pitch and let that 650 eat!