Sea Ray Sundance 310

DarrenC

DarrenC

Member
Jul 10, 2018
164
Boat Info
2001 Sea Ray Sedan Bridge 400
Engines
Mercruiser horizons 350
at wicks end.. I have a 2001 sea ray 310 powered by dual mercruiser 350 mpi horizons. Only getting 3,000 rpm out of motors. Won’t go on plane. So far I have replaced fuel filter, fuel pump, fuel cooler, fuel regulator, new plugs, new belt, had timing adjusted hooked up computer and all checks out, compression each cylinder 195-200. Had diver check bottom and it is clean nothing holding it back, bottom was soda blasted and painted this year. My next step is diver taking props off tomorrow to see if right props or right pitch. Can anyone recommend the right props or something that will perform excellent? Or anything else it may be?Thank you.
 
Here are the props as listed in the 2002 parts manual;

V-Drive
1592724 PROP, 17"X 20"X 1.5" L3BMC NIBRAL H/S
1592732 PROP, 17"X 20"X 1.5" R3BMC NIBRAL H/S
 
Did it ever work right?

Check firing order and spark plug wires are hooked up right.
 
bobeast said:
Here are the props as listed in the 2002 parts manual;

V-Drive
1592724 PROP, 17"X 20"X 1.5" L3BMC NIBRAL H/S
1592732 PROP, 17"X 20"X 1.5" R3BMC NIBRAL H/S
Click to expand...
Would this be the same for 2001
 
Golfman25 said:
Did it ever work right?

Check firing order and spark plug wires are hooked up right.
Click to expand...
Fire order correct, new plugs not sure how old wires are
 
bobeast said:
More than likely. Very few changes between the early 2000's years.

Download your parts manual from here.

Edit: I just checked your parts manual. Yes it is the same.
Click to expand...
Thank you. Would you know what prop works best with this boat?
 
That I couldn't tell you. The factory props seem to work fine for me. I top out at around 32 MPH @ 4800 RPM. No problem getting on plane. That's with V-Drives. I/O would likely be a bit faster.

"best" depends largely on your own expectations. Higher top end, more efficient cruise, best hole-shot. It really depends on what you are looking for. Generally speaking, and assuming everything is functioning as normal, if you reach factory spec'ed RPM for WOT, then you are propped correctly. (on ours, I believe that's 4800.)
 
After all that engine & hull diagnostic work, I gotta go with props. I had the same boat, but can't recall the props. I'm assuming they were factory spec (v-drives) as bobeast reported.

You should have no problem getting on plane in a heartbeat and hitting WOT which is around 4600 (i think). I used to cruise all day long at 3400-3600. That 310 is a spry boat.
 
Just a follow up to all the interested. Props were removed yesterday and they are 16x15. I took them to prop shop to be inspected and he said the size is correct those should get me on a plane even faster. They had a few coats of paint on them so I reconditioned them to new and put back on today. Don’t know what else to look for.
 
DarrenC said:
Just a follow up to all the interested. Props were removed yesterday and they are 16x15. I took them to prop shop to be inspected and he said the size is correct those should get me on a plane even faster. They had a few coats of paint on them so I reconditioned them to new and put back on today. Don’t know what else to look for.
Click to expand...

Your props have obviously been changed by a PO, as 16 x 15 is not spec'ed for any of the engine options offered by Sea Ray. Prop-shop advice notwithstanding, Occam's Razor would seem to indicate you don't have the correct props.

I would suggest asking the prop-shop to loan you a set of 17 x 20's and see if that solves your RPM issue, and gets you on plane. You really want the engines to be in the correct power-band, both at cruise and WOT.
 
bobeast said:
Your props have obviously been changed by a PO, as 16 x 15 is not spec'ed for any of the engine options offered by Sea Ray. Prop-shop advice notwithstanding, Occam's Razor would seem to indicate you don't have the correct props.

I would suggest asking the prop-shop to loan you a set of 17 x 20's and see if that solves your RPM issue, and gets you on plane. You really want the engines to be in the correct power-band, both at cruise and WOT.
Click to expand...

16X15 - he should be banging the red line.
Did the throttle lever throw get checked? That means when the throttle levers are in "full throttle" position are the throttle body butterflies fully open?
 
ttmott said:
16X15 - he should be banging the red line.
Did the throttle lever throw get checked? That means when the throttle levers are in "full throttle" position are the throttle body butterflies fully open?
Click to expand...

Yeah. good point, I suppose if he were over-propped, it would limit the WOT RPMs. Not under-propped as he appears to be. Still, you have to wonder if the PO went to a smaller prop in a misguided effort to correct the wrong problem.
 
bobeast said:
Yeah. good point, I suppose if he were over-propped, it would limit the WOT RPMs. Not under-propped as he appears to be. Still, you have to wonder if the PO went to a smaller prop in a misguided effort to correct the wrong problem.
Click to expand...
Yes good point.
Are these engines injected or carbureted?
 
a 'wild shot' but what if the stringers are full of water?....would that be enough added weight to cause this type of poor performance?.....

cliff
 
Island Time Buffalo said:
It may cause the speed/plane issue, but would something like that affect the RPM's??
Click to expand...

I think so because the extra weight would put additional load on the props/engines not letting them spin up to the normal rpm range....

cliff
 
If it was that heavy, would it be evident by an abnormally high water line on the hull?
 
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