Suzuki 140df advice

ChrisxsRIB · 07 August 2019, 20:46

Hi

I have an 2007 XS600 running a Suzuki 140df which seems to be down on engine RPM.

At WOT I’m hitting around 4500RPM trimmed out. Engine revs to around 3800 RPM and then picks up to 4500 RPM when on the plane.

The boat is coded and therefore, carrying a lot of kit, 8 man life raft, two 8kg anchors and chain etc. Hitting these RPM 4 up with around 50l of fuel.

Running a 3x14x21 prop. Do you think I’m over propped or just heavy?!

Pikey Dave · 07 August 2019, 20:49

Way over propped. I’m running a 4x13.5x19 on a heavy 545 & just touching 6k RPM with 2 up.

xpertski · 07 August 2019, 21:39

I ran a 3x14x19 on that engine and it worked perfectly

Pikey Dave · 07 August 2019, 21:59

Quote:

Originally Posted by xpertski

I ran a 3x14x19 on that engine and it worked perfectly

On which boat & what load though??

jonp · 08 August 2019, 00:46

Over propped for sure, 17 pitch would be closer to the mark or possibly 15.

Searider · 08 August 2019, 10:51

Does the boat live afloat?
Is the bottom clean?
Might there be any water below the floor.

21" sounds too high to me. Is this the propeller that the boat came with? Has performance deteriorated over time?
Is the boat new to you?

xpertski · 08 August 2019, 12:36

Quote:

Originally Posted by Pikey Dave

On which boat & what load though??

Humber Ocean Pro 6.3m. 70litres fuel, usually 2-4ppl aboard. With 2 ppl I got anywhere around 36-38knots and with a full boat of 6ppl got around 33knots

Pikey Dave · 08 August 2019, 12:41

Quote:

Originally Posted by xpertski

Humber Ocean Pro 6.3m. 70litres fuel, usually 2-4ppl aboard. With 2 ppl I got anywhere around 36-38knots and with a full boat of 6ppl got around 33knots

What was the holeshot like with 6 up?

diver 1 · 08 August 2019, 17:24

Chris, I'd reckon over propped. I have various props for that engine in Poole. I use a 17" prop when loaded up with diving kit etc. If you're local you're welcome to borrow a smaller prop see if it helps

xpertski · 08 August 2019, 21:56

Quote:

Originally Posted by Pikey Dave

What was the holeshot like with 6 up?

It was ok but no fireworks

A1an · 09 August 2019, 21:05

and ive just sold my 17 and 19 prop too. Id have lent them to you for testing...typical.

ChrisxsRIB · 11 August 2019, 20:50

Quote:

Originally Posted by Searider

Does the boat live afloat?
Is the bottom clean?
Might there be any water below the floor.

21" sounds too high to me. Is this the propeller that the boat came with? Has performance deteriorated over time?
Is the boat new to you?

Yes it’s the prop I brought the RIB with however, pre coding it always had a decent cruising speed and I never really noticed it cruising at around 3500 RPM. Now I’m carrying a lot of extra weight she feels really underpowered which started me looking at what RPM that engine should rev too.

ChrisxsRIB · 11 August 2019, 20:52

Quote:

Originally Posted by diver 1

Chris, I'd reckon over propped. I have various props for that engine in Poole. I use a 17" prop when loaded up with diving kit etc. If you're local you're welcome to borrow a smaller prop see if it helps

Thank you for the offer, unfortunately I’m actually up in Norfolk. The boat goes to a main Suzuki dealer for her winter servicing so I intend to chat to the guys about it then and hopefully they will have some test props..........

Just really seeing what people’s thoughts were on potential issues.