I just put Pyrometers in the boat. My own comfort zone is up to 1250. What is everyone's opinion? Also fittings are tapped into the top of the exhaust port coming off the cylinder head.

I have my EGT thermocouples in the same spot as yours. I have a digital display - I run mine as high as 1400 * F but I watch it constantly.

what # cyl. did you tap into? if you dont mind me asking

You can go higher in temp you can see numbers in the low 1400's this all depends on hte cylinders youre monotoring and the type of manifold youre using check your plugs and also if you have access to a o2 sensor you can run in the pipe you can really fine tune the performance. Very important check your egts at part throtle because somtimes if the carbs not right in the transsition from primary only to sec you can have a very lean condition that can cause engine damage. Best of luck Sincerely Laz Mesa www.mesabalancing.com

Mesa - Good point.
shortly after a major engine upgrade I checked the EGT's at WOT and all was OK. I was then just cruising and by chance looked at the guage and it was at 1450* - needless to say I just about lost it.
The reason for the upgrade was replacing melted pistons SO if I had to get into it that deep why not add a few more goodies.

I found my old log for my 25' Check back in '94'.
I put thermocouples in all 8 cyclinders in the top of the exhaust port, as you did.
I would move my meter with two inputs to different cylinders. I would see temps from 1300 up to 1430 at WOT. I did see lean spots in the midrange, so I switched over to 1 to 1 throttle linkage. That seemed to help the midrange. I dont have temps before and after for midrange, but I do have temps for WOT. I would see 1370 to 1445 or so at 5600-5800rpm. My favorite cylinders were #1 and #7. On a cold day.. 60* verses 81* temps would go down to around 1380*. My feeling in the end of all the testing was that I was not getting a repeatable reading. Being so close to the valve, I think the results were less than accurate. It would have been nice to put some probes farther down the pipes, but that wasnt doable with the headers I had.
Now I run with a WB02 in dry exhaust and log the info with my EFI ECU. I have only ruined one 02 sensor when I ran it without the mufflers and idled back to the trailer to reinstall them.
I would see constant readings in the mid 1400's all the time. I was using fast response k type thermocouples, if I remember correctly..

Hope this helps.. but my thought is go to the WB02. and not try to read exhaus temps on the water. On the dyno, with dyno headers, different story.. I am using an Innovate unit that I really like.

Dick

havent used them on boats,but extensivly on bikes (2 strokes), do youknow what kind of pistons you have?? the wiseco's Iused to used began melting a littleover 1400. Weather actually played a bigger factorthan initiallythought too, a good front comming in could have a significant impact especiallyif your on the edge. also if traveling altitude needs to be compensated for.