Nice Pair

What does seagrass do to propellers?

Nastybug

Sorry I should have explained that better. Being all over. The sea grass had nothing to do with my props but what it would do is get into the water intakes as small as they are and because my engine heights were so close to the edge of being too high it would cut water flow just enough to where the engine temp would start to rise and then before I could get to top end the guardian would shut me down. I had been up at 2.25 Port and 2 1/8 Starboard above bottom keeping in mind I only have 3 inches of setback and no notch in the bottom of my hull. Motors weren't even I discovered. Anyway I now have them dropped to 2 inches above the bottom and I don't have that problem anymore. My starboard water ramp is off by about half the width of the water intake on the front of drive or I would prob be running them both at 2 1/8 as my water pressure is fine with the port motor where the ramp is straight in line. With 6 inches of setback I could be up at a half inch higher with calmer water for the prop but I'm staying with the current set up for a while.

Nastybug

Ok guys so I got my Shiny new Merc Cleaver 15.25 dia 33 pitch 15 rake Props. Previously I had them with 15 dia with all else same. Just to recap my best run last year was 116mph with my port motor on the limiter 7150 and my starboard at roughly 6800ish. Thats with the original powerhead and when its number six cylinder wasn't working and has pretty much never worked since day 1. Anyway got my new powerhead and the great guys at Coty marine got everything working awesome. So Im currently running my heights at 2 inches above the bottom which Im going to verify with assistance from my new digital protractor. Don't have to level anything. Makes it very easy. I intend on coming up a bit after I get a chance to run with the new props. I don't think Ill see much over last year but the boat has run some great numbers with the terrible heat that we've been having. Im hoping to pic up a few mph. Ive gotten to 114mph under heat conditions and fuel loads that I never could have done it under along with my previous powerhead problem. So my props are on the boat and of course the weather has cooled along with crappy rainy unboatable conditions form Hurricane season. My next service is coming soon with a change of supercharger belts which I wish I had now. Ive been running for about 75 hours or so under last service with very hot conditions. I should have changed the belts at 50 hrs as I know they start to slip as they had in the past when they have run under 95 to 100 degrees continuously for a time. So when I have more Ill be back. Im hoping the extra quarter inch in diameter will take off about 100 to 150 rpm and along with my new fully working powerhead Ill be able to best my last years number by a few with some prop height adjustments. Hopefully the weather will break soon. these damn weather men can't be right for too long.

Tinkerer

I don't know much about outboards but on my IMCO -3 Bravo shortie lower the water pick up was at the point of the drive. I had that slot welded up and recut it right in front of the skag.
At top speed ( 112 mph ) I was picking the water slot out of the water. My prop shafts are 2 inches above the low point on the hull.

Nastybug

Hey Tink, On the 400R Sportmaster lower unit the water pickups are back from the tip of the drive where the propshaft is. There is a grate with 3 slots or slits in it. I believe its three. It is underneath just in front of where the skeg begins to come down out of where the prop shaft torpedo is. Some people widen the wholes where the water actually goes in. I just bought three more years of warrantee and I don't want any problems. Ive had 4 or 5 lowers on my starboard engine and a new powerhead and Mercury and Coty Marine have been Fantastic thru the whole thing. I can't imagine how much things would have cost if I was battling about warrantee issues. Im sure Mercury wouldn't honor any alterations or upgrades. Even having the lowers balanced and Blue Printed can be a problem. I think lowers on the 400R are about 9500 bucks. I Appreciate the info but Ill wait till my warrantees are up.

Nastybug

Well guys, Doesn't look like the weather is going to cooperate any time soon. these damn Hurricanes rolling up the coast just keep coming and ruining what is usually an awesome month in September for us up in NJ. If I get any kind of break in it and the fog goes away I'm going in for a spin at least to get an initial read. Im definitely going up a bit in drive height more as I had mentioned. I had also grabbed what I think was an anchor chain from a navigation bouy about a month ago. I was in the channel and everything but there was a big current going thru a small pass at very low tide and there must have been a ton of slack in the chain as I grabbed it with my port lower skeg. It ripped a jagged edge down the front of the entire skeg. Not deep but it was causing the prop to spin up from air bubbles it created. Anyway I smoothed off the rough side edges that were sticking out to the sides and then smoothed it down with a stone drill bit. I don't think it is taking much away if any but you never know. Cant be more than 1 mph at most so I don't really care. Ill get it fixed this winter. Im going to go out and confirm my heights in the mean time to make sure I know what Im starting with, I didn't lower the motors last time they came down to 2 inches above the bottom.

Double Rigged

iTrader: (1)

Keep at Steve. Dale will be testing soon also!

Nastybug

Hey Ron, Just waiting on some nice weather. When changing engine heights I have a stupid question maybe you can answer. I know the best way to make sure the propshaft on the lower unit is running parallel to the bottom of the boat is to measure/check that the bottom of the boat is level and then check to make sure the propshaft is also level with respect to the hull. I have an electronic protractor that lets me do that. Instead of making boat bottom level and then propshaft level. I just match up the angles it reads between the bottom and drive/propshaft and then I can check or move the heights on my drives accordingly. Rather than go thru all the leveling process I just place this protractor on the hull bottom and then the propshaft. as long as the angles match I know they're parallel and I can then measure to raise or lower the heights. My question is rather than take my props off so I can place this device right on propshaft as my boat is in the water on a lift and Id rather not be fumbling around with them in the water and drop one. It looks to me that the cavitation plate runs parallel to the propshaft and I could just take the measurement off of that and use that reading to make the drive parallel to the hull bottom so I can make a correct measurement when raising or lowering my drive heights. Im not sure if that makes sense at all but I tried. I guess Im just curious if the propshaft and cavitation plate run parallel to each other on the lower unit on the 400R.

ktron

I would use the propshaft...

Taboma

Nasty, At least on my 300XS's, I have confirmed that the cavitation plate is parallel with the prop shaft. I do exactly what your are proposing with my boat on its lift in my dock.