Adapting 260 cowl to 200 2 piece adapter plate questions

[LakeFever]

I did not reed much of this thread but you are using the port side temp sensor and an Autometer gauge, below is what i see on my 280.

With an Autometer gauge my 280 HEAD TEMP runs 150-160 degrees just driving around and at WOT it climbs to 180 degrees give or take (port side merc temp sensor). I don't think the head is actually that hot.

The WATER TEMP is only around 125-130 ish max (you should see 140-145 with a poppet and 2 pc plate). The Autometer gauge hardly moves and I got a digital and confirmed 125 ish.

I just got off the water. Ran 30 gallons of fuel through it. Ran flawless. This is what was happening my gauge was reading way high. I tested the heads, spark plugs, cylinders basically every nook of the motor with my temp gun and the highest number I got was 152. Most were coming in 130-140 even the sending unit itself on the port head was reading 142 which is spot on.

That said I only saw 10psi water pressure maximum. I didn’t ring it out much I’m still breaking it in but I was frustrated to the point of accepting another rebuild today and thankfully the thing is running perfectly. I am going to replace the poppet again as well as another water pump. My thinking is the high pressure I was getting before may have hurt something. Shocking that a hole to triangle made such a huge difference in water pressure. The crazy thing is the temps were getting no higher before I cut the hole out so it was probably ok. Anyways on the road will update more tomorrow thanks gents

good to be on the water. This boat is really nice

[LakeFever]

Dang, I can see not wanting to flog on a new engine, but you might need to give it a little more speed.
From my experience running at low speeds makes the most heat. I try not to run sustained speeds between 7 and 30mph. These speeds usually read head temp of about 170° on my 2.5, and 3 litre engines. If I bump the speed up they run much cooler. I would think half to 3/4 throttle for a hour, and then only short bursts of full throttle for the next hour would be sufficient break in.

As for water pressure. My 150 supermag reads close to what your engine did before you modified the plate. A xri I have has about what your getting now. Both run plenty cool if I stay away from that 7 to 30mph range.

If your getting the tach signal from the regulator, or rectifier, a tach that is capable of reading 12 poles is required.

Are you running a stock lu? What is ptp? What prop?

Stock 40 amp with dual voltage regulators. Volt gauge reading 14ish volts and all seems well. Each regulator has a grey lead that I tapped into one for the tach signal. Yesterday I swapped to the other grey feed and no change. On my last run yesterday I went wide open for a short burst. I brought it up to about 65mph and the tach was 7500-8000rpm which is way higher than I was spinning. The ecu is a stock 200 which limits around 6200 and I let out long before it was topping out. It’s an auto meter tach maybe I need a resistor or something in there or something? I don’t believe their are adjustments to the tach itself that I recall.

I’m running the stock lower unit at the moment with the top three holes plugged on each side. Tempest 27 pitch that I had cut into an et profile. Prop is wicked im really liking it. I have a coned cle and I’m building a brand new jc coned bb lower. I didn’t feel like wasting time installing a new water pump and gear oil to the cle because this stock lower is pristine and all fresh. Want to focus on the jc lower and will run the stock for break in til the jc is done.

[rjdubiel]

One thing that does happen, I have done it also, is over tighten the water pump nuts on the studs. Too tight and it will warp some and not seal correctly. So just get them snug (half ugga dugga) and make sure the water pump base is seated down all the way. That motor has its rings seated and you are ready to lean on it 100% in my opinion. I maybe give a new motors a run quick on the hose, then 15 minutes of easy variable speeds and then let it cool down, then go for it! I may be worng but I just cant baby it much longer than that!! haha. But go out and run that thing from idle to full speed in 20 seconds and see what the water pressure gets to. i bet you get up to 15+ psi at WOT.

[tlwjkw]

That motor has its rings seated and you are ready to lean on it 100% in my opinion. I maybe give a new motors a run quick on the hose, then 15 minutes of easy variable speeds and then let it cool down, then go for it! I may be worng but I just cant (won't) baby it much longer than that!! haha.

my guys would sit on tha bank and jus grimace every time i went out with new stuff.. never destroyed a motor since day one...

ya gotta have confidence in your build.....................

[LakeFever]

I appreciate all the input fellas. I’ve built lots of stuff and usually have good results but with two strokes, especially ones I modified like this one, I’ve had some blow up on the first run, twice in a row in fact. So I’m cautious and not in a hurry and really I want to understand all aspects of this motor. I can’t help itching the curiosity and figuring out what is happening vs what is supposed to be happening. The main issue i have here through this whole ordeal was simply a temp gauge not calibrated to the sender which cost me a week plus of happy boating lol. RJ hit the nail square there and I am very thankful for it. The water pressure issue does have me a little curious though because I can’t see how opening a hole can make that much impact it just doesn’t make sense to me so for the sake of removing that brain itch, I’m going to open the poppet again and take a good look and see. It’s easy to do anyways.

Speaking of poppet what do you guys use to install the plastic washer? I just used a large socket and tapped it in the slot. The one I took out just slipped out easy but the new one was quite high friction fit. I bought it from promarine so I suspect it’s a quality part.


As for the break in? Yes I agree it’s probably fine on the rings now I have run so many heat cycles on this thing and yesterday it ran a lot and ran perfectly well so my confidence to spool it up is setting in. I’m really pleased with the power of this 2.5 is throaty and pulls hard

[rjdubiel]

my guys would sit on tha bank and jus grimace every time i went out with new stuff.. never destroyed a motor since day one...

ya gotta have confidence in your build.....................

on a set of gold rings in a stock bore 260/280/drag some waste half the rings life on break-in! haha.

[rjdubiel]

check the poppet out, then go out, open that motor up for 20-30 seconds once warmed up and see where the water pressure goes to and the temp gauge. If water is above 10 and the incorrect temp gauge does not climb over 185-190 I would say your good to go! do you still have the overheat alarm working? Good luck man.

[tlwjkw]

Speaking of poppet what do you guys use to install the plastic washer? I just used a large socket and tapped it in the slot. The one I took out just slipped out easy but the new one was quite high friction fit. I bought it from promarine so I suspect it’s a quality part.

Did you "stake" carrier?.. i think thats what you're callin' a "plastic washer"....


As for the break in? Yes I agree it’s probably fine on the rings now I have run so many heat cycles on this thing and yesterday it ran a lot and ran perfectly well so my confidence to spool it up is setting in. I’m really pleased with the power of this 2.5 is throaty and pulls hard

understand your position with that motor and your knowledge of tha these motors and wanting ta "get it right"..

think ya doin' way better than most "nuebs" that jus jump in with both feet thinkin' they are ready for anything..

good luck with your venture inta this sickness......................

[LakeFever]

Stake carrier? I didn’t see that anywhere in my manual. I only saw a break down of parts. When I opened the poppet up the plastic washer with the tapered front side just came out. No friction. When I went to install the new one it was tight. I measured with calipers and it was the exact same as the diameter of the hole in the block so it was tight. I used a socket, tapped it in, installed the donut gasket in the middle and stacked the cover and piston parts on with gaskets and bolted it down. I pulled this apart just before this run and it all looked ok but I wonder if I warped that carrier during assembly or if it got messed with too much pressure? I didn’t really look all that close at it I was focused on whether the piston was moving in and out without binding. When I lifted the block up and could release the poppet seeing it was moving and returning freely. I buttoned it all up and here we are. I was thinking maybe my tell tale could be part of the low pressure issue it’s got no restriction on it. 5/16 hose

it is spraying a nice stream always. I had the wife watch close at speed it was good to go. This was part of the reason I was willing to run it so long yesterday. The whole time I was varying Rpm and keeping an eye on wp and tell tale and temp gauge. Most of the time it ran about 8psi

[LakeFever]

check the poppet out, then go out, open that motor up for 20-30 seconds once warmed up and see where the water pressure goes to and the temp gauge. If water is above 10 and the incorrect temp gauge does not climb over 185-190 I would say you’re good to go! do you still have the overheat alarm working? Good luck man.

no alarm but I think this is what I will do next. Any thoughts on getting the tach to read correctly or did I buy a tach that won’t work? Bummer if so it looks great

[tlwjkw]

don't know if its in tha manual but its something most do as a preventative measure... this comes from a lotta very experienced "stock coolin' system" motor guys... up ta you.

[LakeFever]

Ok I searched it out I don’t know my brain damage why I didn’t understand at face value what stake the poppet meant. I see now it’s wedge the sucker in there with stake friction etc. I know for sure the poppet carrier is in tight I had to mash it in there pretty good. I did notice something though that I shrugged off but then in my search I found this and I think I’m going to do the same and make a new washer. I also think I’m going to rig up a way to add my tell tale restrictor on there as well. I’ll also inspect the carrier and all associated pieces again and that should be that. Quite a process lol

[tlwjkw]

agree.. we got pretty proficient at makin' tha alum washers....

think tha "thinking" was that any rotation (for whatever reason) of tha carrier at all could cause tha valve itself ta malfunction.... was jus a little added protection... jmo.

[LakeFever]

Tach settings were wrong I didn't realize it was 12 pulse, the tach was set to 6 so that's a relief and an easy fix. Thinking the exh dump 5/16" hole might be the issue it unleashes a lot of water out there and the factory port is only 3/32" so that would generate a lot more restriction that the 5/16". I think that could be the main low pressure problem here. I'm going to try that first seeing as it runs so good and doesn't overheat as is this is an easy test. Tach adjustment and tell tale reducer and out again another day. Thanks again all, I'm sure most of you can appreciate the brain juggling involved with this so having a place to air thoughts and get guidance has been extremely helpful

[LakeFever]

Took the nozzle off the old cowl, ground it down to the hose diameter and stuffed it in with a tie. Made an aluminum washer I’m going to go through the cooling one more time just to itch that scratch so I can clear it from mind. I tend to cover every obstacle and rarely cut corners because of brain tickles that won’t leave me be. I’m fine with blowing stuff up, I’m not fine with blowing stuff up when I haven’t tried everything I can to prevent it. Washer is 1/8” thick aluminum, 1 3/8” diameter, 3/16” hole.