340 SUNDANCER THREAD

I've had the boat for about two months. Still practicing with the trim tabs. How far down is too far down where I will start creating drag?
 
Hello folks, just purchased a 2003 340 Sundancer, and must say, I love the boat!! One question I have. The smartcraft powers up but says "communication lost". Can anyone quide me on what to check, and where to check it? Thanks, Mark
 
Yesterday when out cruising, the boat was running well and was cruising at around 20 knots very nicely. I had to go through a no wake zone for about an hour, and when I went to throttle back up, the starboard engine lost RPM and then increased and decreased until the engine stopped. It restarted again, but would only hold the correct RPM for a moment and then the RPM would fluctuate and then engine would stop again. No alarms no other indications. I'm thinking a fuel issue and am going to start with the filters. Any other suggestions would be appreciated.
 
Sorry folks, my earlier text stated I was having "communication lost" on Smartcraft, but I should have said System View says "lost communication. Said
 
William

These numbers seem way off to me. I have a 2002 340 with 8.1s and I cruise comfortably on plane at 26 to 27 miles an hour at 3200 RPM. My top end was 43 MPH at full throttle. You did mention the bottom was clean, which I have found to be the biggest contributor to poor performance. I had a Silverton last year that I spent thousands trying to diagnose why it wouldn't get on plane only to find the bottom needed cleaned!
Rob

williamhay said:
Hello rknecht and masterfab. I would like to ask a question reference your comment below. I do have problems reaching my max speed. Not RPM's tho. I have an 06 340 with twin 8.1S v drives. I can hit 4900 RPM's according to my smart craft. But I start to fall off plane at 3800 RPM's and I can only top out at 30mph. The bottom is clean. Could this be related to exhaust issues?
Click to expand...
 
Robf said:
William

These numbers seem way off to me. I have a 2002 340 with 8.1s and I cruise comfortably on plane at 26 to 27 miles an hour at 3200 RPM. My top end was 43 MPH at full throttle. You did mention the bottom was clean, which I have found to be the biggest contributor to poor performance. I had a Silverton last year that I spent thousands trying to diagnose why it wouldn't get on plane only to find the bottom needed cleaned!
Rob
Click to expand...

agreee, The RPMs seem high and speed top speed is low... The '06 weighs more than my '01, but I have 7.4s with less HP and I plane at about 3200 RPM. I have had similar numbers with fouled bottom and props... I do not this this is an exhaust issue.
 
I agree - my boat is a bit unique, but even so, these numbers are way way off. I can hold plane down to 2600 - 2700 RPM, depending on load, resulting in speeds of 15 to 18 knots. I can cruise anywhere between 3000 and 3400, with 3200 to 3300 being particularly comfortable for the boat, and resulting in around 27 knots. Top speed is 39.6 knots, or just a bit over 45 mph.

I do have enlarged tabs, but I mostly retract them unless I am running at low speeds in rough seas or confined areas. If your running gear is in good order, you need to inspect your bottom.

Dale
 
I am a new boat owner. Just bought a 88 340 Sundancer. I have to re-bed rails. Is this job difficult? Do you have to remove headliner to get at bolts? How long to do the job? In addition where can I buy the rubber moldings for the front windshield? Thanks for your help. Dave
 
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I have a friend with an 01 340 and the 6.2l MPI motors. He's having problems with his port motor not achieving the desired rpms. Does anyone know what the compression should be on this motor?
 
Bucit said:
I have a friend with an 01 340 and the 6.2l MPI motors. He's having problems with his port motor not achieving the desired rpms. Does anyone know what the compression should be on this motor?
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My 5.7s on my 300 was 130-140 psi... It is important that there is consistancy in the numbers....
 
For anyone interested, a few posts ago I was looking for some answers regarding "communication lost" error on my smart craft. I have learned, and it worked for me anyway, that if you unplug the harness on the back of the smart craft, then plug them back in, it resets something that makes them work. FYI for anyone experiencing the same problem.
 
Bucit said:
I think he said all cylinders were at 180 but one was at 145ish.
Click to expand...

One or two Cylinders gave a low compression value. This might be normal, since each cylinder will not give the exact same pressure value.What is NOT normal if the pressures vary by 15% or more. That's right, the individual cylinder compression readings of each engine cylinder can not vary more than 15%... and this is how you can find out:

  1. Grab a calculator and multiply the highest compression reading that you recorded by .15.

    Let's use the following Compression readings to explain the point:
    • Cylinder #1 175 PSI.
    • Cylinder #2 160 PSI.
    • Cylinder #3 165 PSI .
    • Cylinder #4 95 PSI .
    • Cylinder #5 160 PSI.
    • Cylinder #6 165 PSI .
    • Cylinder #7 170 PSI .
    • Cylinder #8 165 PSI .
  2. The next step is to do the math: 175 x .15= 26, 175-26= 149.
  3. So then, 149 PSI is the lowest possible compression reading that any one of the rest of the engine cylinders can have. Any compression reading below this.. and that engine cylinder will misfire.
  4. This means that Cylinder #4 is the one causing the Misfire
 
That would seem correct. I feel im at least 10 mph off top speed. Can you tell me what the pitch is on your props? That is the next thing I am going to check.
 
Robf said:
William

These numbers seem way off to me. I have a 2002 340 with 8.1s and I cruise comfortably on plane at 26 to 27 miles an hour at 3200 RPM. My top end was 43 MPH at full throttle. You did mention the bottom was clean, which I have found to be the biggest contributor to poor performance. I had a Silverton last year that I spent thousands trying to diagnose why it wouldn't get on plane only to find the bottom needed cleaned!
Rob
Click to expand...

Rob, what is the pitch of your props?
 
Hi -

Maybe this can help with the RPM issue. I had problems with my '07 340 with 8.1's speed / RPM's when I moved from ~200' to ~6300' at Lake Tahoe. I never did push my top speed at 200', but I had a big problem when moving to altitude (80% air density of sea level). I could barely plane and the RPM's were 2800 / 3400 on my engines.

Here are some of my stats.

Pre-move (200' above sea level): As far as I could tell, normal performance to what has been reported here.

Post-move (6300', filled up with ethanol fuel after arrival, non-ethanol unavailable): Top speed was 23mph barely on plane with full throttle and my engines at 2800 and 3400 RPM, respectively.

Post-move (added ethanol buster to fuel, never had to worry about that): Top speed of 31mph with engines at 3650 and 3850 RPM, respectively.

Post-move (ethanol buster + repropped from 18 x 21.5" RH prop and a 18 x 22" LH prop to 18 x 19 for both props): Top speed of about 33mph with engines at ~4300 RPM. Both engines now in sync again. I run it at about 3800 / 27mph.

So, if you're not at any significant altitude, my thoughts would be to make sure you have non ethanol gas or an ethanol buster additive. I couldn't believe the difference.

-Gary
 
chameleon said:
Hi -

Maybe this can help with the RPM issue. I had problems with my '07 340 with 8.1's speed / RPM's when I moved from ~200' to ~6300' at Lake Tahoe. I never did push my top speed at 200', but I had a big problem when moving to altitude (80% air density of sea level). I could barely plane and the RPM's were 2800 / 3400 on my engines.

Here are some of my stats.

Pre-move (200' above sea level): As far as I could tell, normal performance to what has been reported here.

Post-move (6300', filled up with ethanol fuel after arrival, non-ethanol unavailable): Top speed was 23mph barely on plane with full throttle and my engines at 2800 and 3400 RPM, respectively.

Post-move (added ethanol buster to fuel, never had to worry about that): Top speed of 31mph with engines at 3650 and 3850 RPM, respectively.

Post-move (ethanol buster + repropped from 18 x 21.5" RH prop and a 18 x 22" LH prop to 18 x 19 for both props): Top speed of about 33mph with engines at ~4300 RPM. Both engines now in sync again. I run it at about 3800 / 27mph.

So, if you're not at any significant altitude, my thoughts would be to make sure you have non ethanol gas or an ethanol buster additive. I couldn't believe the difference.

-Gary
Click to expand...

I'm fairly sure I have factory props (18x21.5) If I were to change to a higher pitch, would that increase my speed? What are the down sides to a higher pitch prop?
 
Bill

Per my survey, the props are Nibral 18 x 22 with a medium cup.

Rob


williamhay said:
I'm fairly sure I have factory props (18x21.5) If I were to change to a higher pitch, would that increase my speed? What are the down sides to a higher pitch prop?
Click to expand...
 
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