Welcome to Pursuit Boats Owners Forum

We are a boating forum for owners of Pursuit Boats to enthusiastically discuss all aspects of Pursuit Boat ownership. Whether you are looking for your first Pursuit or currently own one, you are sure to feel at home on PursuitBoatOwners.com

You are currently viewing our boards as a guest which gives you limited access to view most discussions, articles and access our other FREE features. By joining our free community you will have access to searching the forum topics, post topics, communicate privately with other members (PM), respond to polls, upload your own photos and access many other special features. Registration is fast, simple and absolutely free so please, join our community today!

Fuel efficiency/speed on Cummins 250B

ImageHave a question or issue that is model specific? The is the forum to discuss general information regarding all Pursuit Boats.

Topic author
Sharkguy05
Junior Member
Posts: 22
Joined: Mon Jul 27, 2020 5:37 pm
Vessel Info: 1999 3000 express
Has thanked: 1 time

Fuel efficiency/speed on Cummins 250B

Postby Sharkguy05 » Mon May 23, 2022 11:34 am

I have a 99 express 3000 with cummins 250 4bta's and was curious what everyone elses fuel consumption/speed is when fully loaded.

I run about 20knots at around 2400 rpms and I get around 18Gph is my estimate. WOT I am averaging 26knots, they are numbers from days with about 3ft around 7sec..

I looked at the factory specs and numbers are way off as far as speed goes so I was curious.


Dan1
Member
Posts: 68
Joined: Sun Apr 19, 2020 11:17 pm
Vessel Info: 3000 Express Cummins 4BTA's
Been thanked: 23 times

Fuel efficiency/speed on Cummins 250B

Postby Dan1 » Wed May 25, 2022 7:05 am

Your speed/RPM/fuel burn is way off indicating over-propped or or a fuel/air issue.
Your risking serious engine damage if what you are saying is correct.

Get an accurate WOT throttle reading, you should be seeing 3100 RPM’s in gear under load, 3200/3300 in neutral engine hot.

Get a harbor freight digital tach and find out what those engines are spinning at before they implode.

MarkT
Senior Member
Posts: 583
Joined: Tue Apr 05, 2011 10:42 pm
Home Port: Mattituck, Long Island
Vessel Info: 1999 Pursuit 3000 Express, twin Cummins 4-BTAs
Has thanked: 9 times
Been thanked: 84 times

Fuel efficiency/speed on Cummins 250B

Postby MarkT » Thu May 26, 2022 9:54 pm

I agree with Dan1 above, something is not right there. I have owned my 3000 Express with Cummins 4BTAs since 2003 and have always checked my fuel burn since then. My average fuel burn for the season is less than 7 gph total. I cruise at 23-2400 running 22-23.5 kts. WOT is 3100-3150 and I see up to 31.5 kts. I would love to see a picture of your turbos, because they must be handling some heat. Any black smoke? How many hours and what props are you running? 3 or 4 blade?

Topic author
Sharkguy05
Junior Member
Posts: 22
Joined: Mon Jul 27, 2020 5:37 pm
Vessel Info: 1999 3000 express
Has thanked: 1 time

Fuel efficiency/speed on Cummins 250B

Postby Sharkguy05 » Wed Jun 01, 2022 10:59 am

I have digital tachs connected in conjuction, WOT I get up to 3100 RPMS, I cruise at 2400rpms 20-21 knots, no smoke. Aftercoolers just rebuilt and they were in decent shape. Turbos look decent. Had the wheels redone 2 yrs ago I want to say at 19-23 or 19-22, I dont recall if they are 3 or 4 blade off top of my head. Fuel consumption is about on par with factory. Just my top-end is not getting the speed I'd like. Engines have 700hrs one them. Turbos run at about 190 deg F when shot with a heat gun. Exhaust temps were within specs when checked 2 yrs ago. Not really sure what else is could be going on. Bottom and wheels are pretty clean. Injectors are 1 season old, and new air filters. Not sure what really could be going on and what else to check

MarkT
Senior Member
Posts: 583
Joined: Tue Apr 05, 2011 10:42 pm
Home Port: Mattituck, Long Island
Vessel Info: 1999 Pursuit 3000 Express, twin Cummins 4-BTAs
Has thanked: 9 times
Been thanked: 84 times

Fuel efficiency/speed on Cummins 250B

Postby MarkT » Wed Jun 01, 2022 4:24 pm

If you see 3100 RPMs the engines seem healthy. 20-21 KTS seems low at 2400, should be closer to 22.5 23.5. 26KTS at 3100 is slow. I think your props are the culprit, or you run heavy with the trim tabs full bow down!

Topic author
Sharkguy05
Junior Member
Posts: 22
Joined: Mon Jul 27, 2020 5:37 pm
Vessel Info: 1999 3000 express
Has thanked: 1 time

Fuel efficiency/speed on Cummins 250B

Postby Sharkguy05 » Thu Jun 02, 2022 10:48 am

I do run heavy this is with full load out of gear, full fuel tanks, full water and 7 people on board plus coolers, ice etc. I only use my tabs to help get on plane easier, then retract them and only use a tad if i need to balance a load or something. Props call for 19-23 I turned them 2 seasons ago at 19-22 I believe was hard to read the marks but prop shop lasered them. I am looking into some prop tuning on SB MAr but yes I agree I am about 3knts off all the way through. Im going to start making a chart and see what i run and more accurate fuel burn and going to laser the rpms this weekend and fine tune it. Not really having any issues just want to make her more efficient if i can

Topic author
Sharkguy05
Junior Member
Posts: 22
Joined: Mon Jul 27, 2020 5:37 pm
Vessel Info: 1999 3000 express
Has thanked: 1 time

Fuel efficiency/speed on Cummins 250B

Postby Sharkguy05 » Tue Jun 07, 2022 1:35 pm

well the cheap laser i bought didnt seem consistent enough so I am borrowing one from the boat yard and going to re-run but looks like i may be 100rpms high on my gauges from what the actual engines are spinning which would explain slower speeds but then also means i'm only topping at 3000rpms and not 3100/3150. So I would need to adjust the pitch on the wheels. It's always something...

Topic author
Sharkguy05
Junior Member
Posts: 22
Joined: Mon Jul 27, 2020 5:37 pm
Vessel Info: 1999 3000 express
Has thanked: 1 time

Fuel efficiency/speed on Cummins 250B

Postby Sharkguy05 » Tue Jun 07, 2022 1:36 pm

side note when i ran the other day it was like a 1-2ft chop and had 3/4fuel and only 2 on board and i hit 28.5knots wot

MarkT
Senior Member
Posts: 583
Joined: Tue Apr 05, 2011 10:42 pm
Home Port: Mattituck, Long Island
Vessel Info: 1999 Pursuit 3000 Express, twin Cummins 4-BTAs
Has thanked: 9 times
Been thanked: 84 times

Fuel efficiency/speed on Cummins 250B

Postby MarkT » Wed Jun 08, 2022 10:05 am

Maybe back off a little pitch on those wheels.
These users thanked the author MarkT for the post:
Sharkguy05 (Wed Jun 08, 2022 1:30 pm)


Topic author
Sharkguy05
Junior Member
Posts: 22
Joined: Mon Jul 27, 2020 5:37 pm
Vessel Info: 1999 3000 express
Has thanked: 1 time

Fuel efficiency/speed on Cummins 250B

Postby Sharkguy05 » Wed Jun 08, 2022 1:30 pm

MarkT wrote:Source of the post Maybe back off a little pitch on those wheels.

That's the plan after i verify the rpm's and tachs

Return to “General Pursuit Boats Forum”



Who is online

Users browsing this forum: No registered users and 2 guests