Boat

Have Boat Questions? Ask a Boat Repair Expert.

Connect one-on-one with {0} who will answer your question

This answer was rated:

Have purchased boat with CumminsQSB 305 hp engine. Have been…

Have purchased boat with CumminsQSB...
Have purchased boat with CumminsQSB 305 hp engine. Have been told one can increase horsepower by changing a chip in engine.If so what is up and or downside?Thank you
Show More
Show Less
Ask Your Own Boat Question
Answered in 4 days by:
10/27/2016
Marine Mechanic: K. Kergan, Marine Mechanic replied 5 years ago
K. Kergan
K. Kergan, Marine Mechanic
Category: Boat
Satisfied Customers: 1,031
Experience: 24 yrs exp. Inboard/Outboard mechanic Mercury/ Mercruiser, Volvo Penta and OMC, Johnson/Evin.
Verified

Hi, my name is Kerry

Here is a list of performance chips for a 5.9

https://www.chipexpress.com/products/cmd-cummins-mercruiser-diesel/qsb/

It looks like the same engine can go from 230 hp all the way up to 480 hp depending on the chip.

Engines need to run under load, if you increase the horsepower dramatically without changing the gear

train to compensate, the engine won't last.

Increasing the horsepower will also allow the engine to achieve a higher maximum RPM which could also damage the engine.

If the boat seems a little gutless, try the next chip up. That would be 255 hp but keep an eye on your RPMs, the engine shouldn't

be able to rev super high even at full throttle.

K. Kergan
K. Kergan, Marine Mechanic
Category: Boat
Satisfied Customers: 1,031
Experience: 24 yrs exp. Inboard/Outboard mechanic Mercury/ Mercruiser, Volvo Penta and OMC, Johnson/Evin.
Verified
K. Kergan and 87 other Boat Specialists are ready to help you
Ask your own question now
Was this answer helpful?

How JustAnswer works

step-image
Describe your issueThe assistant will guide you
step-image
Chat 1:1 with a marine mechanicLicensed Experts are available 24/7
step-image
100% satisfaction guaranteeGet all the answers you need
Ask K. Kergan Your Own Question
K. Kergan
K. Kergan
K. Kergan, Marine Mechanic
Category: Boat
Satisfied Customers: 1,031
1,031 Satisfied Customers
Experience: 24 yrs exp. Inboard/Outboard mechanic Mercury/ Mercruiser, Volvo Penta and OMC, Johnson/Evin.

K. Kergan is online now

Related Boat Questions
I have a 6.2 MPI Horizon. SN T4-R420GHT TOW 322548. It was
I have a 6.2 MPI Horizon. SN T4-R420GHT TOW 322548. It was fitted new in my boat which was built in 2006. I can't find it"s HP . Some seem to think it is 350HP. Others say 320 and some info suggests 3… read more
Jason
Jason
Marine Mechanic
24,193 satisfied customers
Im thinking of purchasing 306 GW canyon 2011 with engines
Im thinking of purchasing 306 GW canyon 2011 with engines 250 hp 4 stroke one manufactured 2008 and one 2009 ( new when boat first bought 2011) what is difference between those 250's and 4. 2 liter 25… read more
Jason
Jason
Marine Mechanic
24,193 satisfied customers
I have a 2004 305cid mercruiser engine that has seized with
I have a 2004 305cid mercruiser engine that has seized with milkshake oil present, Can/should I replace 305cid with a 350cid longblock/reman unit? … read more
Jason
Jason
Marine Mechanic
24,193 satisfied customers
1998 hydrasport Vector 22' WA with new 4.3 vortec on OMC
1998 hydrasport Vector 22' WA with new 4.3 vortec on OMC Cobra stern drive. Current prop is 15.5 x 15. very hard to get on plane without extensive use of trim tabs. WOT 4200-4300 rpm once I am able to… read more
Jason
Jason
Marine Mechanic
24,193 satisfied customers
What do I need to do to increase my 7.4l mercruiser from 310
What do I need to do to increase my 7.4l mercruiser from 310 hp to 340 hp … read more
Noel Schembri
Noel Schembri
Marine Mechanic
Diploma
3,046 satisfied customers
I purchased a 1998 sportstar nineteen with no engine, all I
I purchased a 1998 sportstar nineteen with no engine, all I have is the serial number from the registration. trying to find out what the engine I need is. The serial number I have is IC956453 … read more
Jason
Jason
Marine Mechanic
24,193 satisfied customers
What is the difference from Mercury 90HP with jet pump on a
what is the difference from Mercury 90HP with jet pump on a Lowe 1860 Tunnel jet and putting on a 115HP… read more
Jason
Jason
Marine Mechanic
24,193 satisfied customers
Hello I have a 2001 125hp mercury. What can I do to increase
Hello I have a 2001 125hp mercury. What can I do to increase the hp of the outboard? My boat is rated for a 150 hp motor. Larry… read more
Jason
Jason
Marine Mechanic
24,193 satisfied customers
I had a 2005 Four winn 210 Horizon I bought new that was 22
I had a 2005 Four winn 210 Horizon I bought new that was 22 ft. long with 280 hp volvo penta engine and volvo single prop outdrive with a 19 or 21 pitch prop not sure which ran very well and strong wi… read more
Jason
Jason
Marine Mechanic
24,193 satisfied customers
how can I improve the performance and top end speed on a Skeeter
how can I improve the performance and top end speed on a Skeeter 180sx with 115 yahama. Also improve the hole shot. Is their anything I can buy to increase the horsepower… read more
Tan
Tan
MerCruiser Certified Technician
Certified Marine Technician
11,409 satisfied customers
I have a 1986 22ft larson with a mercruiser 350 cid in my boat.
I have a 1986 22ft larson with a mercruiser 350 cid in my boat. The plastic cover over the carb reads 200/v8. What horsepower is this engine?… read more
Noel Schembri
Noel Schembri
Marine Mechanic
Diploma
3,046 satisfied customers
I have two mercruiser motors a 470 and a 488 as I understand
I have two mercruiser motors a 470 and a 488 as I understand it both have the same blocks if I install the 488s inlet manifold to the 470 so I can use the 4 barrel carbi will this improve the hp of th… read more
Jason
Jason
Marine Mechanic
24,193 satisfied customers
can I install a V-8 (305 or 350) engine into my 1989 19 Searay
can I install a V-8 (305 or 350) engine into my 1989 19' Searay Bowrider 140 hsp AlphaOne Sterndrive...need more power for skiing...but donot want to purchase another boat..also, how tough would it be… read more
Whitecap36
Whitecap36
Service Manager/Technician
Vocational, Technical or Trade Scho
1,557 satisfied customers
I have a 7.4L (330hp) mercruiser with silent choice exhaust.
I have a 7.4L (330hp) mercruiser with silent choice exhaust. I'm looking at gill wet exhaust headers to improve performance. I'm told I won't get enough bang for my buck with this improvement. For the… read more
Dominick
Dominick
Marine Mechanic
Vocational, Technical or Trade Scho
1,009 satisfied customers
can you purchase a chip to increase horsepower/torque for a
can you purchase a chip to increase horsepower/torque for a 2007 d9 575 volvo diesel marine engine?… read more
Dominick
Dominick
Marine Mechanic
Vocational, Technical or Trade Scho
1,009 satisfied customers
Hey guys, Im disabled and cant afford brand new engines.
Hey guys, I'm disabled and can't afford brand new engines. I have a 30 ft. pacemaker sf powered by crusader model 220's some have told me they are 305 's and some have told me they are 350's 260 hp, t… read more
capt ron 1959
capt ron 1959
Owner/Marine Mechanic
Vocational, Technical or Trade Scho
348 satisfied customers
I am considering a boat and I have a choice between motors
I am considering a boat and I have a choice between motors of a Mercruiser 4.3 MPI fuel injected V6 220 horse and a Volvo GL/SX 5.0 220 HP V8. Can you help me decide objectively?… read more
Infiniti Nissan Specialist
Infiniti Nissan Specialist
Master Technician
Vocational, Technical or Trade Scho
915 satisfied customers
I want to put a 115 Mercuty Outboard on my 16 Ft Starcraft
I want to put a 115 Mercuty Outboard on my 16 Ft Starcraft Deck Boat. However, it is to expensive to trade the present 90HP (2007) Optimax 2cyl 4 cyl for a 115HP. Is there a way to increase power of t… read more
Dominick
Dominick
Marine Mechanic
Vocational, Technical or Trade Scho
1,009 satisfied customers
Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

JustAnswer in the News:

Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.

What Customers are Saying:

Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help.

Mary C.Freshfield, Liverpool, UK

This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!!

AlexLos Angeles, CA

Thank you for all your help. It is nice to know that this service is here for people like myself, who need answers fast and are not sure who to consult.

GPHesperia, CA

I couldn't be more satisfied! This is the site I will always come to when I need a second opinion.

JustinKernersville, NC

Just let me say that this encounter has been entirely professional and most helpful. I liked that I could ask additional questions and get answered in a very short turn around.

EstherWoodstock, NY

Thank you so much for taking your time and knowledge to support my concerns. Not only did you answer my questions, you even took it a step further with replying with more pertinent information I needed to know.

RobinElkton, Maryland

He answered my question promptly and gave me accurate, detailed information. If all of your experts are half as good, you have a great thing going here.

DianeDallas, TX

< Previous | Next >

Meet the Experts:

Ted G.

Ted G.

Marine Mechanic

4,145 satisfied customers

40 years experience, Safe boating instruct., Failure Analysis, Expert Witness

Dominick

Dominick

Marine Mechanic

1,009 satisfied customers

25 Years Experience as Mechanic, 20 Yrs Boat Yard Owner/Mechanic, Factory Certified

John White

John White

Marine Mechanic

306 satisfied customers

11 years experience working on outboards, inboards, sterndrives & pwcs

Jason

Jason

Marine Mechanic

24,193 satisfied customers

Degree in Marine Technology. Gas and diesel marine mechanic.

Tan

Tan

MerCruiser Certified Technician

11,409 satisfied customers

40 yrs. experience with complete engine repairs both inboard/outboard and MerCruiser Certified Technician.

Jeff G.

Jeff G.

Marine Mechanic

4,730 satisfied customers

42 years experience, Certified Master Technician, All Major Outboards, Sterndrives, Hi-Performance

Noel Schembri

Noel Schembri

Marine Mechanic

3,046 satisfied customers

Advanced technical diploma

< Previous | Next >

Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Show MoreShow Less

Ask Your Question

x