Limited RPM's

[bud37]

Marty.....My guess here is....chances are there wont be any codes since it is fine now......make sure they check for codes in memory, if available.....really they would have the laptop connected with the right program and out for a ride with the engines under load and watch all the parameters.

I hear ya on the gong show....

[Marty]

So after running code scans and turning up nothing mechanical a sea trial was conducted today and the captain said that upon gradual acceleration there were no alarms sounded and with trimming he was able to achieve 3200 ish RPM's on each engine. His diagnosis is that prop pitch is likely not proper..... on the 326 I have Mercruiser 5.7L 350 MPI's and based on the last survey there are 3 Blade Bronze alloy props 18/21's. I guess this could be the issue, but I am unclear and didn't have the chance to ask why would I get alarm alerts when heavily accelerating and not be able to disarm unless returning throttles to zero thrust? Plan is for the prop shop to evaluate once the boat is pulled after labor day as kids sports and school absorb all weekends afterwards.....any thoughts as to if this sounds probable?

[tomschauer]

Marty, if you were able to achieve 4k previously with the same props, that's not the issue.
Did they check the fuel pressure while running (under load)?
As far as the alarms, on a 2000, it should have been high engine temp, low oil pressure or high trans temp.

[Marty]

Yes especially on our leg between kincardine and tobermory I encountered 6-8 footers off my port?starboarded and we're chasing waves for 50 miles. Engines purred liked kittens back and forth and only on the last trip back to port last season did RPM's become an issue.....

[Marty]

Port/Stern...

[Marty]

Source of the post Marty, if you were able to achieve 4k previously with the same props, that's not the issue.
Did they check the fuel pressure while running (under load)?
As far as the alarms, on a 2000, it should have been high engine temp, low oil pressure or high trans temp.

Source of the post Marty, if you were able to achieve 4k previously with the same props, that's not the issue.
Did they check the fuel pressure while running (under load)?
As far as the alarms, on a 2000, it should have been high engine temp, low oil pressure or high trans temp.

Captain did mention that the scan revealed a good amount of operating time revolved around the engines operating in the 3200-3400+ range,.......cannot get there today though....

[bud37]

Source of the post Yes especially on our leg between kincardine and tobermory I encountered 6-8 footers off my port?starboarded and we're chasing waves for 50 miles. Engines purred liked kittens back and forth and only on the last trip back to port last season did RPM's become an issue.....

Two things come to mind from this new info......problem started after crashing around in rough seas, maybe some debris loosened off the tank floors...possible restriction. The second is you are not far off what the boat had been running at, have you added a lot more stuff on board since then?

Did he have the diagnostic tool hooked up to the engine while he was out on the trial.??

[Viper]

Something sounds weird. Really need to try and duplicate running conditions and try to get that alarm to trigger again with a diagnostic tool hooked up. She sounded off for a reason. Hopefully you can find out why while she's still in the water, it may prevent you from having to remove props etc.

In the meantime, you can contact Carver and ask for prop specs and expected performance curves for your particular package. Then you can compare the prop info with what you currently have by either diving or waiting until haul out.

What marina did the sea trial Marty?

[Marty]

I have reached out to Carver and from a weight standpoint perhaps a little extra water so I'm guessing less than 1000 lbs with full coolers/food etc. Marina is Bayport

[Marty]

So in speaking to Carver the alarms may be the result of the engines not getting enough water either bad impellers or weeds in the scuppers or strainers. My mistake was interpreting an alarm from behind the dash in the cockpit during acceleration was a reflection of an engine alarm that could be read by a code scanner. I will have to check the strainers upon next visit as this may be a strong probability as i pulled a salad out of the genny strainer this last weekend. In respect to the weight question I always now run with completely full fresh water tanks 40 gals which is and extra couple hundred pounds (still have to replace the float sender) and full fuel tanks as my gauges aren't as reliable as I would like them to be. I've added a couple of batteries as well and generally travel with a good handful of adult beverages which probably adds another couple hundred pounds. Only other question was related to engine compression which I am waiting for the report from the Marina techs, but assuming that they had been completed and the fact that they had told me that my engines are in great mechanical condition I have to believe that weight is the culprit.

Ill likely run my water tanks dry, take the tender off the back, burn off some fuel and head out for my own sea trial to confirm my now suspicions and will update....