Proud new owner of 89 Sundancer 340. Just a few issues...

K

Ky Tundra

Member
Sep 5, 2017
92
Kentucky
Boat Info
1989 Sundancer 340
Engines
Twin 454 Mercruisers with v-drives
I wasn't really searching for a new boat but a friend forwarded me a great deal on Craigslist and now I have another boat. This forum was great for helping me make the decision and fixing some problems along the way. Finally got everything in running order and took our maiden voyage yesterday.
The boat was seemingly well taken care of by the last few owners. Sadly the previous owner bought it last summer and then passed away unexpectedly. Has twin 454s with about 1100 hrs. Bottom is in decent shape, needs paint, but isn't too dirty. About half full gas tanks (fuel was in the boat, no idea of age. I assume its from at least last year) and full of water. Plugs, wires, caps all done last year. Fires right up, idles around 600 RPM according to the tach. Have a few questions:
  • Have a Floscan fuel burn gauge under the helm. Was this a factory option? is there anyway to insure they are reading correctly or any calibration needed? Is the gauge giving a combined reading for both motors? It was showing around 4 GPH at low rpms and jumping to 8-10 range when on plane around 2500 RPMs. (see below)
  • How should I deal with existing fuel? Is there anything I can treat it with at this point? Do I burn through this and then add more or add new on top of it? I'm in Kentucky and we are nearing the end of our boating season.
  • I don't think I'm hitting a proper WOT. We had odd conditions yesterday, with a strong wind blowing up river and a decent current. Going up river my port engine could only reach about 2700 RPMs. Starboard still had a little to go. At 2500 RPMs I was on plane at about 15 knots per GPS, floscan said 8-9 GPH. At 1600 RPMs I was running about 7-8 knots and burning 4 GPH. Any thoughts???
  • Starboard transmission is making some noise. clicking. You can hear it at idle. Fluid was just a little low. Topped it off. Should I be concerned? Anyone used Lucas in these trannies. I had good luck with it once on an old truck.
  • The boat is not as responsive as other twin engine boats I have had when docking. Needs more throttle to make it come around. Is it safe to keep the RPMs slightly higher than idle and still be able to shift between forward and reverse?
Thanks for helping on these questions. I'm sure I'll have more...
 
Welcome to CSR!

Existing Fuel - This might be causing your low RPMs and WOT issue. If there's no way to tell when it was filled and what kind of fuel is in the tanks I would try to burn off as much as possible, maybe even drain some if you can get rid of it safely. Change the water/fuel separator filters.

WOT/Speed Issues - This could be the fuel or a dirty bottom and running gear. Even a small amount of growth can cause what you mention. There's a good chance the issues you are experiencing are bottom related. Do yourself a favor and have the bottom cleaned first before anything else.

Transmission Noise - My port makes a noise when at idle. It goes away with the smallest throttle increase so I wouldn't be overly worried. I'm not a fan of additives so I'd shy away from going that route.

Responsive - My boat is also a little sluggish around the docks, especially reverse. I wouldn't wan't to shift gears while the engine is above idle. I'd just get used to giving her a little throttle when necessary while in gear.
 
I have a 1988 340 Sundancer. At about 3500 RPMs, I go about 24 knots (depending on currents and wind). 4 GPH at 1600 RPMs and 8 knots sounds pretty close to what I get. Although I don't have a fuel monitor. That's just my own math, which could be wrong!

I haven't noticed sluggish response at idle, but this is my first twin engine boat. So, I don't really have a good comparison.

Dan
 
Please see my comments below in RED. I hope that they will give you some insight. Enjoy the boat as they are great if taken care of...

[QUOTE="

  • Have a Floscan fuel burn gauge under the helm. Was this a factory option? is there anyway to insure they are reading correctly or any calibration needed? Is the gauge giving a combined reading for both motors? It was showing around 4 GPH at low rpms and jumping to 8-10 range when on plane around 2500 RPMs. (see below)
Floscan is not factory option I am sure but I can not offer any other experience but you could always google if you need to calibrate it.
  • How should I deal with existing fuel? Is there anything I can treat it with at this point? Do I burn through this and then add more or add new on top of it? I'm in Kentucky and we are nearing the end of our boating season.
You could always see if you have a local fuel polishing company? They would be able to remove the water from the tanks. If it were me I'd top off the tanks with fresh fuel and add some Seafoam to the tanks before doing so. That will help boost the fuel that is in the tanks and even it out. Seafoam will clean up any tarnish or gunk. I would definitely replace the fuel filters. There are two per engine. One on the front bulk head which are water separators (keep a close eye on these if you know there is water) and one on each engine.
  • I don't think I'm hitting a proper WOT. We had odd conditions yesterday, with a strong wind blowing up river and a decent current. Going up river my port engine could only reach about 2700 RPMs. Starboard still had a little to go. At 2500 RPMs I was on plane at about 15 knots per GPS, floscan said 8-9 GPH. At 1600 RPMs I was running about 7-8 knots and burning 4 GPH. Any thoughts???
You are not reaching wide open rpms. Should be 4200 to 4400 rpms at WOT. I would add fresh fuel and some Seafoam and try again. Fuel flow sounds inline with what I'd expect. Many things can contribute to not reaching your rpms... bad fuel, plugs, wires, timing off, wrong props...
  • Starboard transmission is making some noise. clicking. You can hear it at idle. Fluid was just a little low. Topped it off. Should I be concerned? Anyone used Lucas in these trannies. I had good luck with it once on an old truck.
Yes, make sure that they are full of transmission fluid. It may be worth your time to replace the ATF. If completely empty they take 3 quarts each. They shouldn't make noise and yes, I would be slightly concerned and possibly they are miss aligned?
  • The boat is not as responsive as other twin engine boats I have had when docking. Needs more throttle to make it come around. Is it safe to keep the RPMs slightly higher than idle and still be able to shift between forward and reverse?
These boats are great and will take some getting used to. With the prop pockets and small rudders it will not move as easy as a non pocket boat. It's normal to have to bump the throttle but try not to slam them into gear with the engines revved up. It's easier on the system to change gears and then rev them up and not slam them into gear.

Thanks for helping on these questions. I'm sure I'll have more...[/QUOTE]
 
Thanks for the quick responses. For what it's worth, the boat was surveyed by previous owner in May 2016 and I received a copy. The boat was being sold "as-is" and the price gave me some room for repairs. I was also able to speak with the mechanic that worked with the previous owner. Neither the mechanic nor the survey mentioned any problems.

I'll pull it out and check the bottom.
 
Thanks for the detailed responses.

Pyrojodge said:
Please see my comments below in RED. I hope that they will give you some insight. Enjoy the boat as they are great if taken care of...

[QUOTE="

  • Have a Floscan fuel burn gauge under the helm. Was this a factory option? is there anyway to insure they are reading correctly or any calibration needed? Is the gauge giving a combined reading for both motors? It was showing around 4 GPH at low rpms and jumping to 8-10 range when on plane around 2500 RPMs. (see below)
Floscan is not factory option I am sure but I can not offer any other experience but you could always google if you need to calibrate it.
  • How should I deal with existing fuel? Is there anything I can treat it with at this point? Do I burn through this and then add more or add new on top of it? I'm in Kentucky and we are nearing the end of our boating season.
You could always see if you have a local fuel polishing company? They would be able to remove the water from the tanks. If it were me I'd top off the tanks with fresh fuel and add some Seafoam to the tanks before doing so. That will help boost the fuel that is in the tanks and even it out. Seafoam will clean up any tarnish or gunk. I would definitely replace the fuel filters. There are two per engine. One on the front bulk head which are water separators (keep a close eye on these if you know there is water) and one on each engine.
  • I don't think I'm hitting a proper WOT. We had odd conditions yesterday, with a strong wind blowing up river and a decent current. Going up river my port engine could only reach about 2700 RPMs. Starboard still had a little to go. At 2500 RPMs I was on plane at about 15 knots per GPS, floscan said 8-9 GPH. At 1600 RPMs I was running about 7-8 knots and burning 4 GPH. Any thoughts???
You are not reaching wide open rpms. Should be 4200 to 4400 rpms at WOT. I would add fresh fuel and some Seafoam and try again. Fuel flow sounds inline with what I'd expect. Many things can contribute to not reaching your rpms... bad fuel, plugs, wires, timing off, wrong props...
  • Starboard transmission is making some noise. clicking. You can hear it at idle. Fluid was just a little low. Topped it off. Should I be concerned? Anyone used Lucas in these trannies. I had good luck with it once on an old truck.
Yes, make sure that they are full of transmission fluid. It may be worth your time to replace the ATF. If completely empty they take 3 quarts each. They shouldn't make noise and yes, I would be slightly concerned and possibly they are miss aligned?
  • The boat is not as responsive as other twin engine boats I have had when docking. Needs more throttle to make it come around. Is it safe to keep the RPMs slightly higher than idle and still be able to shift between forward and reverse?
These boats are great and will take some getting used to. With the prop pockets and small rudders it will not move as easy as a non pocket boat. It's normal to have to bump the throttle but try not to slam them into gear with the engines revved up. It's easier on the system to change gears and then rev them up and not slam them into gear.

Thanks for helping on these questions. I'm sure I'll have more...
Click to expand...
[/QUOTE]
 
Sorry Ky, I didn't mean to be harsh but to me a 16 month old survey is not adequate. These symptoms you described would have all been discovered during a new survey at least allowing you to know what kind of expense you would be looking at down the road. I owned an '89 340da for 4 years and I know these boats pretty well.

You haven't said what you paid for the boat but if you have to replace a trans, props, shafts, etc. the good deal goes away quickly. And I mention this for others, to illustrate the importance of a recent survey.

I sincerely have my fingers crossed for you that these issues are minor and you can begin to enjoy these great boats.

Shawn
 
NorCal Boater said:
Sorry Ky, I didn't mean to be harsh but to me a 16 month old survey is not adequate. These symptoms you described would have all been discovered during a new survey at least allowing you to know what kind of expense you would be looking at down the road. I owned an '89 340da for 4 years and I know these boats pretty well.

You haven't said what you paid for the boat but if you have to replace a trans, props, shafts, etc. the good deal goes away quickly. And I mention this for others, to illustrate the importance of a recent survey.

I sincerely have my fingers crossed for you that these issues are minor and you can begin to enjoy these great boats.

Shawn
Click to expand...

Not a problem. I get it. I guess that's true, a lot of issues can pop up on a boat in 16 months. Thanks for the crossed fingers. I'll keep you guys posted on what I found out. Luckily a good friend has the same boat and owns a trailer so we can pull it fairly easily. Save me a few bucks!

PS I have a beautiful 1991 Sea Ray 210BR for sale. I bought it 5 years ago from the original owner and he was meticulous. I don't think the boat has ever been rained on. We have kept it inside the entire time we've owned it too. If you know anyone interested send me a message. I'll work on getting an ad together for it.
 
Ky Tundra said:
Not a problem. I get it. I guess that's true, a lot of issues can pop up on a boat in 16 months. Thanks for the crossed fingers. I'll keep you guys posted on what I found out. Luckily a good friend has the same boat and owns a trailer so we can pull it fairly easily. Save me a few bucks!

PS I have a beautiful 1991 Sea Ray 210BR for sale. I bought it 5 years ago from the original owner and he was meticulous. I don't think the boat has ever been rained on. We have kept it inside the entire time we've owned it too. If you know anyone interested send me a message. I'll work on getting an ad together for it.
Click to expand...

Did you list it in the classifieds here? Also, include price, pictures, and location.
 
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