Official (1998-2002) 310 Sundancer Thread

Grec said:
I'm new to the 310, so pardon the newbie questions. Can someone tell me where the sea cock is for the A/C unit's cooling water? I've searched the manual and the boat and I haven't been able to find it. Thanks
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Under the port transmission if u have v drives.
 
My boat has twin 357 Horizons with 225 hours on them. At idle the tac on the starboard engine stays at a constant 1,000 RPM, but the engine sounds like it is fluctuating between around 800 RPM and 1100 RPM and then back to 800 RPM (just my guess). Not having had inboards before, I didn't know if the exhaust system could cause it to sound like it was fluctuating like that as the exhaust water passed through the muffler. So, I started the port engine.

The port engine seemed to have a similar fluctuating sound, but not as pronounced. The tac for the port engine was also pinned at 1,000 RPM. Once the port engine was running though, I noticed that the sync meter started fluctuating in time with the sound the starboard engine was making despite both engines reading 1,000 RPM. That made me think that I was hearing what I suspected and that the tacs were just not reading properly.

After a while, the sync meter evened out, but the starboard engine still sounded like it was still fluctuating. At higher speeds, there is no fluctuation or any indication of a problem. It gets up on a plane nicely and sounds smooth. But when I drop it back to an idle, the sound of what seems like a fluctuating RPM returns.

The previous owner said that he recently replaced the fuel pressure sensor on the starboard engine. Assuming that the sound I'm hearing is actually the RPM fluctuating, could it be the result of a bad MAP sensor?
 
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These engines have a pronounced cam lope at idle. It would come across as a rhythmic "thrumming" sound. Does that describe what you are hearing?
 
Yes - kind of a slow throb. The cycle is rhythmic and consistent over about a 3-5 second period. What is a cam lope?
 
Grec said:
Yes - kind of a slow throb. The cycle is rhythmic and consistent over about a 3-5 second period. What is a cam lope?
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Cam lope is caused by cam profiles which hold both the exhaust and intake valves open at the same time for a short period of time (called overlap). This moves the power band into the upper RPM, but affects idle. Marine cams tend to have more overlap than most automotive cams resulting in a distinctive thrumming at idle.

That said, if each cycle is lasting 5 seconds, either your mental clock needs calibration, or something else is going on. I would expect each cycle to last no longer than a couple of seconds.
 
Well, when I was there I was more concerned with what was happening than how long it lasted, so it could also be a memory issue as opposed to a mental clock. My Dad used to say, "I have a terrific memory, but it's very short". ;)

I'll pay more attention to the timing, but as I think about it, it probably was a shorter cycle than I originally reported. Thanks for the information!
 
Checked again today - 1 second, maybe 2, so you had to have called it right bobeast. Thanks
 
Bennett Drop Fin Trim Plane Assembly

Just put a set of these on my 01 310. Identical to the original, but for the drop down fins. This has made for a totally better handling boat. No longer an issue to get on plane and no longer need full down trim for cruise. No more nose high!
 
Thanks, and you were able to use the old cylinders?
 
Yes and the original backing plate. You use the new hinge and tabs. Easy peasy. I bought my 310 new and am astounded @ the difference this easy mod has made.
 
We try to do a little improvement project on our 310 every year. This season we had a new Charger (Pronautic 12 2 10)put in at the beginning of the season figuring next years project would be 3 AGM batteries so I would no longer have to service the poorly placed batteries every year. WRONG! Port starting battery shit the bed on the 4th. Emergency crossover worked great but the weather was iffy so I spent the morning putting 3 Duralast group 31 AGMs in and changing the charging profiles on the charger.. It'll be nice not having to service them. Anyone else have any experience with a similar set up? Thoughts/concerns? Thanks.
 
Bugsy22 said:
We try to do a little improvement project on our 310 every year. This season we had a new Charger (Pronautic 12 2 10)put in at the beginning of the season figuring next years project would be 3 AGM batteries so I would no longer have to service the poorly placed batteries every year. WRONG! Port starting battery shit the bed on the 4th. Emergency crossover worked great but the weather was iffy so I spent the morning putting 3 Duralast group 31 AGMs in and changing the charging profiles on the charger.. It'll be nice not having to service them. Anyone else have any experience with a similar set up? Thoughts/concerns? Thanks.
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Interesting choice with the 12-2-10 on a 310 DA. Do you not have at least 3 batteries? What was the original charger?
 
techmitch said:
Interesting choice with the 12-2-10 on a 310 DA. Do you not have at least 3 batteries? What was the original charger?
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Yes, 3 batteries. Port starting that also runs blowers, bilge and cockpit lighting. 2 in parallel that run the house bank and start the starboard motor. Weird setup but thats the way SeaRay designed them. It has the emergency starting crossover too. The OEM charger was a 2 bank 20 amp and it was never left on. We plan on leaving the new one on all the time since it shouldn't overcharge ever. We run a genny when were out for long periods so no worries there.
 
Bugsy22 said:
Yes, 3 batteries. Port starting that also runs blowers, bilge and cockpit lighting. 2 in parallel that run the house bank and start the starboard motor. Weird setup but thats the way SeaRay designed them. It has the emergency starting crossover too. The OEM charger was a 2 bank 20 amp and it was never left on. We plan on leaving the new one on all the time since it shouldn't overcharge ever. We run a genny when were out for long periods so no worries there.
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That 310 with 5.7L EFI's and BIII's is an excellent set up, especially in fresh waters.
 
My vacu flush pump began tripping the breaker this weekend. Is there any other option but a pump replacement? 2001 310 v-drives.
 
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