Twin Perkins 165HP Turbo Uneven fuel burn

[yknotgo]

Hello,
My dad purchased a 1970's 32' Luhrs a couple months ago. I can't remember exact year right now. Anyways, it's powered by twin Perkin Diesels, 165HP with turbos. Anyways, when we moved the boat from where he bought to where he is keeping it, an 80 mile trip, we fueled up the tanks (separate 80 gallon tanks) and one took substantualy more fuel than the other, about 1.5 times as much as the other if I remember correctly. Recently, we went fishing, and did about a 40 mile round trip run and fueled up the boat. One tank took 9 gallons while the other took 21. Trying to figure out what would be causing such a difference in burn rates. Any ideas? The one that burns more fuel also burns oil, so we are thinking that engine may be needing an overhaul. No idea as to how many hours are on the motors, assumed to be very many. Just looking for ideas. If he could get the one engine to be as efficient as the other, that'd be great, but isn't looking to spend money right now, just doing homework

Thanks for any ideas.

Grady

 

[rayacky]

Re: Twin Perkins 165HP Turbo Uneven fuel burn

Hi Grady, may be worth checking the fuel returns are going to each tank or are thy both returning to one?? Just a thought. Cheers Ray.

 

[alldodge]

Re: Twin Perkins 165HP Turbo Uneven fuel burn

Hello,
My dad purchased a 1970's 32' Luhrs a couple months ago. I can't remember exact year right now. Anyways, it's powered by twin Perkin Diesels, 165HP with turbos. Anyways, when we moved the boat from where he bought to where he is keeping it, an 80 mile trip, we fueled up the tanks (separate 80 gallon tanks) and one took substantualy more fuel than the other, about 1.5 times as much as the other if I remember correctly. Recently, we went fishing, and did about a 40 mile round trip run and fueled up the boat. One tank took 9 gallons while the other took 21. Trying to figure out what would be causing such a difference in burn rates. Any ideas? The one that burns more fuel also burns oil, so we are thinking that engine may be needing an overhaul. No idea as to how many hours are on the motors, assumed to be very many. Just looking for ideas. If he could get the one engine to be as efficient as the other, that'd be great, but isn't looking to spend money right now, just doing homework

Thanks for any ideas.

Grady

Do the engines appear to run the same? Are you giving one more throttle then the other. I'm thinking one engine is over fueling. Pull the exhaust hose off the turbo and compare the amount of soot you see

 

[yknotgo]

Re: Twin Perkins 165HP Turbo Uneven fuel burn

Thanks for the replies. Now that you mentioned it ALLDODGE, the motor that burns more fuel is also the motor that the throttle is substantially further forward than the other motor, at same RPMS, so maybe the gauges are not reading correctly. I think we can buy one of those gun things that you point at the belt or something and it'll read the RPMS and see if there is a large difference between the two...
Not sure I understand how to measure the soot. Would I just put the exhaust hose into a gallon bottle for each and see which one contains more after running it for a couple mins?

 

[alldodge]

Re: Twin Perkins 165HP Turbo Uneven fuel burn

Thanks for the replies. Now that you mentioned it ALLDODGE, the motor that burns more fuel is also the motor that the throttle is substantially further forward than the other motor, at same RPMS, so maybe the gauges are not reading correctly. I think we can buy one of those gun things that you point at the belt or something and it'll read the RPMS and see if there is a large difference between the two...
Not sure I understand how to measure the soot. Would I just put the exhaust hose into a gallon bottle for each and see which one contains more after running it for a couple mins?

With the throttle substantially further forward I'm pretty sure your engine needs help and requires more fuel to run the same RPM. Start off with looking at your air filter/screens and see if they need cleaning or replacing. If you pull the exhaust hose off there should find quite a bit of black suet. The suet build up will be because of over fueling.

Have you changed the fuel filters lately? If you can get ahold of a turbo boost gauge try to find out what the reading is. Don't know if your engines have waste gates, but if they do check to see they are in working order.