correct injectors for 671Jt TI's

[hATTISFACTION]

HELP !!!
the 1976 42C I purchased last fall seems to have the wrong injectors. When I had the boat surveyed the engine surveyor simply mentioned that I might want to
replace the current large injectors with smaller ones to get better engine life. I had a local highly recommended detroit mechanic take a look this past weekend since I get a LOT of smokel stain on the transom and he told me the injectors were 92-95's and actually were for 8V92
engines. He contacted Johnson and Towers who have now told us that although they had the original engines the final modifications were done by Covington Deisel.
J&T did say that they thought 90's would be correct but my mechanic says this is a radical reduction.
We are now trying to reach someone at Covington.
ANY help is sincerely appreciated ..
thanks

[captddis]

The 390 SHP 671TIs had m95 injectors. Dave

[hATTISFACTION]

Dave,
thanks for the response. These engines are rated at 450 hp. Port has only 12 hrs starboard 242. I have had the props repitched down from 24 X 28 to 24 x 24 as she was topping out at 22knts, way more than I needed and I want these engines to last as long as possible.
I'm thinking the 95's you mention would be the correct injectors to put in.These are not the same as the 92-95's I have now are they ??Would there be a prefix of 71 befor the 95 to differentiate the 671 from the 892 engine series ??I usually only run the boat at 1800 since my last boat was a Hatteras 41 with natural 8v53's
and I'm vappy with 16-18 kts.thanks again for your advise.

[captddis]

The prefix is not an indication of what engine they fit. The 450hp engines I have worked on use a 9215 injector or a JT injector which is a m95 with a special tip which is replaced by a m15. I have never heard of a 9295. Could it be a 9225? Dave

[hATTISFACTION]

Dave , your are right on again.
They are 9225 's that I have now and I really think the M15 is what I should put in . Do you think this will help clean up the exhaust some ?? thanks

[captddis]

The smaller Injectors should help. You may want to check compression while changing injectors and do a complete tune up. I would check with Covington as to what they used to be sure to get the right parts. I have always found Covington helpful. Good luck, Dave

[hATTISFACTION]

Interestingly Covington Diesel has looked into this and found that the original injectors were N90's. Hatteras also confirms that. Would anyone know if I replace the 9225 injectors with the original N90's how much this will change the performance. I am interested in longevity not speed. Props have already been taken back down to original 24 x 24.Hopefully the 42C will cruise 16-18.
I suspect these engines will not be putting out 450 hp any longer
but more like 435. All comments appreciated.

[captddis]

According to the info I have they would put out 350 SHP @ 2300 and 360 SHP @ 2500 . With the N 90s

[hATTISFACTION]

do your records show the HP ratings with the M15 injectors ? thanks
I know I need to get those 9225's out. Those N90's certainley should get more life out of the engines and run cleaner.