How man hrs before rebuild on blown 540?
 

I am looking at buying a 27 fever with a blown 540 with dual carbs. Could anyone tell me how many hrs I could get out of it before having to rebuild? And how bad the fuel consumption might be if only hitting wot every so often and cruising at 45-50 the rest of the time. Thanks

depending on the parts used during assembly,and how hard it is driven,il say 250 hrs on valvesprings,rings at 500 hrs,this is if you keep up with the regular maintanance,like changing oil&folter every 12 to 15 hrs,fuel filter every 15 to 20hrs.

forgot fuel mileage,due to the power the engine will make,you will have a prop with a lot of pitch,so your rpm,s at crusing speed will be lower,that means fuel mileage will be better than a normally asperated engine at crusing speeds.

So as long as I dont run it wot much and do regular maintainance it should be at least 250 hrs before valvesprings, thats good. Would you be wiery of buying this boat or not? Hes wanting 20,000 for it. I want a good sounding fast and reliable boat that I wont have to spend my whole paycheck in fuel or fixing it.

How much power does the engine make. You can assume a conservative BFSC on a carb'd blower motor of 0.55. For example, if it makes 750 hp and you have it running flat out, it would burn 413 lb/hr or about 63 gal/hr.

27 fever should go 50mph using only about 200-225hp. You could expect it to burn 19 or 20 gph at that speed, I would venture to guess.

no mater what used boat you buy,you will have to put fuel in it,and with any used boat,things can go wrong,would i be wiery about bying it,no,but i am a glutten for punishment.:lolhit:

do a compression test and leakdown on the motor

mike

+1

with all due respect, you are making your decisions on the wrong basic parameters. if this motor has been run in service for any meaningful length of time then your false assumption is that it was cared for and run in good and proper fashion... a very risky assumption to make.

if the motor is " fresh from rebuild" with zero or low time, you are assuming that it was built correctly and will not blow up in the first 3 hours as so many motors on here do...

so... either you research the build in excruciating detail both in the parts that went in and who did it and the raw dyno data or you do a forensic examination with bore scope and oil analysis and cutting open filters and leak downs and all that goes along with that...

OR you assume the thing will need $5000 worth of work in the first year and adjust the price accordingly...

there are people that would run that motor for 500 hours and it would be as new... and there are people that, like some that have posted on this board ( my oil pressure went to zero so i ran it wide open to see if it would come back or is 575 degrees of oil temp too much ? or i have a noise in my valve train and the motor is on 7 cylinders , do you think i can run the rest of the season like that ?) where after 50 hours the motors would be scrap no matter how good they were to start .

there is no advice you can recieve that will take the place of your own assumption of risk, good judgement and due dilligence.

my advice is to ignore everything anyone tells you and treat this purchase in the same manner that you would any purchase that has huge risk of financial disaster associated with it... and then act accordingly.

That is exactly correct. No BS There