LandNSea 1pc plate - CCMS

**25two.stroke** · 04-02-2021, 03:00 PM

Chris I was gonna text you with some questions about this plate but I noticed you've been a bit more active on here in the past week I figured I'd put it here for all to see. On this 1pc plate/tuner from Landnsea, I'm just lookin at it and wondering how to install it. I did a search here and on the interwebs and can't find much info on these plates. Anyone who has experience with these please chime in!

So...looking at this plate there's no threads where the upper motor mount bolts go. On the first 1 pc plates by merc was it this same way? Do you thru-bolt these and put a nut on the back? Was that just a landnsea thing? I know the later 2.5 plates are tapped and you thread a motor mount bot in there, torque to 150 ft-lbs and wire tie it. In one of the pics here I put one of those motor mount bolts on the hole to show the size difference. It almost looks like one could just tap the hole with the same thread pitch as the later 2.5 motors and just mount it like that, but is there enough meat there? It looks like there's about 1" of aluminum and at that thread pitch there would be like 13 threads holding, is that enough? Basically my main question is: how do you attach the upper bolts.

Second question: the later plates had a bolt and retaining clip for the water tube and the 2 pc early plates had no retaining clip. Does this matter? Should I drill and tap it like the later plates as an upgrade? Because the water tubes aren't flared, does that clip really do anything? This clip is shown in the drawing as #21

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**Dave S** · 04-02-2021, 06:18 PM

If I am looking at the pixs rite....you going to have a mixmash of gasket surface ...... unless your running an old 2.0.....?

**25two.stroke** · 04-02-2021, 06:46 PM

Not a 2.0. what gasket surface doesn't look right? Chris told me LandNSea designed these for 2.4 Bports, but I have not laid any gaskets down yet, maybe I should worry about that before I think about mounting it to a pivot tube...

**ChrisCarsonMarine** · 04-03-2021, 11:45 AM

Not sure what Dave is referring to...the plate will fit your BP properly.The top mount bolts go through,with locknuts inside.The retaining clip retains the grommet,not the tube,I would glue the grommet into the adapter,and not worry about the clip.The tube can be pulled out/pushed back in.

**Dave S** · 04-03-2021, 05:22 PM

Just looking at the size of the bottom of the tunna.....looks like the old 1750 ..... Maybe the top is newer style.... Circa 1980

......

**25two.stroke** · 04-04-2021, 12:41 PM

Thank you both! I dummied the gaskets up and they match perfect. Good info on the grommet retainer, that makes a little more sense.

So I guess the upper motor mount bolts to use with this one are smaller dia. than the ones that thread into the later 1pc plates. I will find a set of bolts to suit.
Would there be a downside to tapping these holes? Is there enough meat there to support it or would it crack? I won't do it if this plate was designed for thru-bolting, but I'm just wondering.

**tlwjkw** · 04-04-2021, 01:19 PM

tha hole size in tha tiller will have some bearing on bolt size also.. production should be 7/16ths and high perf will be 1/2 inch.. also ya might check size of and number of dump holes for coolin' and pressure.. seems like it had two "large holes" that may/may not work with a steel sleeve motor.....

**25two.stroke** · 04-04-2021, 01:50 PM

Yeah those have already been tapped and plugged. Waiting on a tiller and can so I guess I'll let that dictate the bolts. Thank you for that note. Do those 7/16" bolts ever shear? I have honestly never put solid mounts in a production can so I have no experience adding shear stresses to the little bolts. I've only ever messed with rubber mounts on little bolts and solid mounting the bigger bolts.

I have seen more than enough solid mounts shatter their housings like what happens on most 250xs motors. But I have never seen a sheared motor mount BOLT in a 2 stroke. I have, however, seen sheared motor mount bolts in some of the new 4strokes

**tlwjkw** · 04-04-2021, 01:56 PM

i've never seen one shear/break (2.0's ta 2.5's) production or hi perf but that doesn't mean it hasn't/can't happen..

**Dave S** · 04-04-2021, 06:58 PM

Could ya post Pixs of the top of the plate? Thanks.

**Mrzip** · 04-05-2021, 05:01 PM

I got One of Those On a 260. Works Fine

**25two.stroke** · 04-05-2021, 06:36 PM

You can see it in the back of this pic next to a F1 pan. Yeah the casting/strengthening around the rear ph studs might impede the exhaust a little, but I don't think its enough to worry about. I'll try to post a pic of it with the gasket on it.

I think that's what you were talking about Dave the rear of the exhaust port looks like the first 150/175 exhaust ports. Even though the Land N Sea plate has this same profile I think it came into being much after merc revised the exhaust port to be rectangular.

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**Dave S** · 04-05-2021, 07:23 PM

No more worries at this end..anymore...... it's cast up good.....if not leaks....1750 has a wee different on the water around the ports.....not good when mated to a 2.4 block.