Engine fails to accelerate and vibration

[lastclipper]

The first time we have taken the boat out since a cold snap here on Florida's SW Coast. We encountered the issue of not accelerating normally and failed to obtain planing speed. There was a vibration as we accelerated as well. Someone has told me it is either fouled or bent prop or perhaps an out of round shaft. Any ideas would be appreciated. We are new to powerboats.

Thank you,
Mark and Jan Pyle
Dragonfly - 2012 Ranger Tug 29S

 

[trailertrawlerkismet]

If the boat performed ok the last time you had it out then I’d suggest you have algae growth on your boat hull and or barnacles attached to your drive gear. In Florida, unless you use the boat regularly, you’ll get growth within 3 to 4 weeks.....depends on how long ago the boat bottom was painted with anti fouling paint. Algae and barnacles can drastically slow a boat down and or cause unusual things to happen. You can hire a diver to bottom clean your boat or find a sandbar/shallow water and do it yourself. Either way this would be a good first and less expensive step. Does the engine rev up when put into neutral? If not it could be fouled fuel, which would require new fuel filters as a start. If it does rev up you could have seaweed or something wrapped around the prop. Away from the dock, unless you get into the water to check, you can put the engine in reverse, give it a little RPM’s to try and dislodge anything that may be clinging onto the prop. Let us know what you find.

Jim F

 

[BB marine]

The first time we have taken the boat out since a cold snap here on Florida's SW Coast. We encountered the issue of not accelerating normally and failed to obtain planing speed. There was a vibration as we accelerated as well. Someone has told me it is either fouled or bent prop or perhaps an out of round shaft. Any ideas would be appreciated. We are new to powerboats.

Thank you,
Mark and Jan Pyle
Dragonfly - 2012 Ranger Tug 29S

Mark, I commented on your post AGLCA today and will add to it. Your post on the AGLCA indicated you ran aground and had this issue after running aground. You had a diver inspect your prop and found no issues or damage. Based on your post AGLCA it ran fine before running it in shallow water ( sand Bar). One would conclude that the loss of power and vibration was caused from this event.
I realize that power boating is much different than sailing. Engine running conditions can be effected by more than a bent prop especially if the diver tells you it isn't bent. There are many things that could cause a loss of power but first you must determine how much power loss and how much speed you have lost. What is the time frame between the time you ran a ground and the boat sat at the dock ? What was the condition of the bottom when you had the diver inspect the prop? Was that recent ? Did you check fuel filters? Did you see what your boost numbers were when trying to bring the boat to planing speeds? Generic questions why is my boat vibrating and not accelerating can lead to running around in a circle.
Here are some questions to answer.
Was the boat performing good before you hit the sand bar? What was the operating rpm at high cruise?
Did the boat performance immediately change after hitting the sand bar?
How long has the boat sat since hitting the sand bar?
How long has the boat been in the water and is the bottom clean?
Does the turbo sound like it is spooling up and what is the boost pressure ?
What is the maximum rpm the engine will turn? WOT wide/open/throttle ( now)
What was the maximum rpm the engine would turn before hitting the sand bar?
When you hit the sand bar did you check the sea strainer to see if you slugged the raw water cooling with mud and sand?
Have you inspected fuel filters ?

Answering some of these basic questions and giving a detailed description of past operation and now current operation helps
others help you troubleshoot the issue.

 

[lastclipper]

Brian,
I do not think we “ran aground.” We were in the mid-channel and slowed slightly in the sand, I guess. It was barely perceptible but noticeable anyway. The Diver measured with a metal device.
1. The Boat sat for a month between the incident and the next trip.
2. I am unsure how to determine the power loss.
3. The bottom is reported as free of barnacles ( unsure, however, as the Diver is due back at this time)
4. Fuel filters and virtually everything on and in the engine is new… just had everything changed.
5. I am sorry, I do not know what boost number means?
6. The Boat was performing well before the sand strike
7. It sat for about a month
8. The bottom is reported as clean
9. Turbo sounds normal (Boost Pressure?)
10. I will have to look at max rpm again. When last we were out, about 3350 produced 12 to 13 KTS
11. Sea Strainers are all excellent and
12. Fuel filters are new.

 

[lastclipper]

Jim, thank you for the reply. Our diver will be here this week to check for fouling. He reported on the last visit that he removed all attached barnacles and algae. The shaft turns easily by hand so I do not think that is it but my mechanic will be here tomorrow to troubleshoot. I appreciate you input.

Mark

 

[Trisailor]

You might double check the cutlass bearing. I had a similar issue after picking up an errant crab pot warp around the prop and shaft. After a cols swim at 630 AM, discovered about 1/4 inch of play side to side in the prop/shaft. The subsequent replacement of the bearing during a planned yard period solved the issue.
Now an unabashed plug for Fluid Motion:
A brand new R31 just showed up at our club. The new owner, who did the factory delivery, is just n=beaming. After my tour the other day, all I can say is WOW! What a nice boat. Nice thing is, my 10 year old R27 compares very favorably to the brand new R31. FM sure builds a nice quality boat.

 

[BB marine]

1. The Boat sat for a month between the incident and the next trip

Possibly enough time to get enough fouling on the bottom. It doesn't take much to reduce performance.

2. I am unsure how to determine the power loss.

If you don't have recorded performance numbers use the numbers posted below and compare to your current performance numbers.

I'm posting an example of a R29 similar to your boat. These numbers are from a R29 owner,Yanmar 260, with a clean hull..
7.0 knots at 2300 rpm 3.8 Gph
8.1 knots at 2550 rpms 5.0 gph
10.9 knots at 3000 rpms 7.9 gph
17.1 knots at 3950 rpms 14.1 gph - max speed

5. I am sorry, I do not know what boost number means?

Boost numbers or boost pressure PSI comes from the turbo. The max boost pressure reading for your engine should be 30 psi +/- 1 @ wot. A reduced boost pressure can be a cause of loss of power.

6. The Boat was performing well before the sand strike

Do you have recorded performance numbers of your boat from before the sand strike that you can use to compare the difference. (Example before the sand strike the engine turned 4000 rpm WOT after 3500 rpm)

10. I will have to look at max rpm again. When last we were out, about 3350 produced 12 to 13 KTS

Was this WOT? The max recommended rpm is 4000 rpm +/1 100rpm,

I would have the diver check the bottom and clean. Have him confirm the prop is clean. Then take the boat out for a sea trial. Record a few performance numbers and compare to the ones posted above. If the engine appears to operate ok, turbo boost is good, clean fuel filters but performance numbers seemed to be below what they were before the (sand Strike) and a vibration is felt. You may have bent a blade or blades on the prop. Not likely but possible. ( What happened to cause the change? Sand strike? Good Luck.

 

[trailertrawlerkismet]

Can you rev the engine up when you put the shift lever in neutral? If so this would narrow the search for the solution to the problem. Update us when you have new info so we can all learn from your experience.

Jim F