m25 xp What is the top speed and RPM ?

[John]

My C30 has a m25XP and I want to no what speed I should be runing at.I no i should run at about 2/3 full power but Im not sure what that is I have a three blade prop . And at 2000RPM im runing about 4.5 kts but at 2500 I run at 5.25kts There are alot of people that go alot faster? I never run more then 2300 .The reason im wondering about this now is that im haveing a starting problem . My moter allways starts on the second try it seens not to matter if i use the glow plug or not I have some fuel seeping from the starbord side of the moter around the fuel filter?Its not enough to make a drip but it is wet.It could be oil but i dont think so.Could i be sucking some air and need more cranks to presher up to start? how about this. Could i be runing to slow and fouling my injectors? I ran about 1/2 hr at 2500 and the next day it started up on the first try on the first crank maybe the prop is no good some one painted it with a copper anti foul and it is pitted up a bit . I use a fule additive for smoke and bugs and stuff.when sailing i reach about 4.5 to5 kts with new sails150% head sail and FB main I have a tall rig my bottom needs to be striped and re done what do you guys think.

 

[Alchemist]

Speed? Depends on your BOAT

The speed of your boat under sail or power is a function of the waterline length (theoretically 1.34 times the square root of your waterline length (in feet)). Assuming that you have the proper engine (You probably do if your engine was specified and installed by Catalina), and the correct propeller, you should be able to reach this speed at about 3/4 throttle.I believe that WOT (Wide Open Throttle) for the Universal M25XP is 3250 - 3300 RPM. Therefore, assuming that you don't have too much crap on the bottom of your boat, flat water and calm winds, you should be acieving this speed at about 2400 - 2500 RPM. Either a two or three bladed, fixed, folding, or feathering prop should be able to achieve this as long as the prop is properly sized and pitched.There is NO reason not to run your engine as fast as 80 - 90% of WOT for hours at a time. You won't hurt it. Diesels like to be run HARD. Running a diesel underloaded will result in an increase in carbon and crap in your exhaust.SteveAlchemist

 

[Tim McCarty]

I agree with John

I have a C310 with a M25XP diesel. I also have a 3 blade prop and typically cruise at about 2800 rpm, however I will run the engine wide open many times at the recomendation of the diesel guy who services the boat. Given the fact that mine is a new engine, I am also varying the rpms quite a bit when I am motoring for more than an hour or so.

 

[Tim McCarty]

excuse me...I agree with Alchemist...

it's still early in the morning...good luck John...

 

[redfishnc]

It's the prop size and pitch that matter ......

it seems like the prop problem i am going through has forced me to learn quite a few things. when you say you have a three bladed prop; do you have a 13x10, 14/13, or any other combination? i have a 14x9 1/2 gori folding two blade and i desire to have better manueverability and little more grunt. i also want to put the boat into gear at idle and let it already be engaged even at the expense of a little sailing speed. i am already obviously not in a hurry at 5 or 6 knots... so what is your boat model, engine and prop size and pitch?