Volvo Penta 5.7 GXi Rebuild — Rough Idle, Chirping and Noise Under Load

Looking for input from experienced marine engine rebuilders or Volvo Penta mechanics.

I have a 2008 Chaparral 224 Extreme with a Volvo Penta 5.7 GXi and approximately 600 hours. It had been an extremely reliable engine since I purchased the boat in 2014, but it was recently rebuilt after cylinder #7 tested at about 60 PSI.

One person performed the machine work and internal rebuild, while a second mechanic reinstalled the manifolds, pumps, accessories, ignition components and completed the final setup.

During the initial water test, the engine bogged badly under acceleration and had 2 decent fluid leaks. I was told the bogging was related to ignition timing and that the engine still needed to be dialed in... So we took it out of the water and took it back to troubleshoot resolve the timing as well as the leaks...

The mechanic later said the issues were corrected and sent me videos of the boat running around 38 MPH. I went to pick up the boat from mechanic and took is straight to the river...On my first outing after picking it up:

• I heard a chirping or squeaking sound from the engine area.
• No fluid leaks
* then I pulled away from the dock and slowly motored at approximately 5 MPH for the first 10 minutes.
• Then the first gentle attempt to get on plane went smoothly.
• The idle seemed rough/more engine vibration than I would expect and actually more in line with the way it was behaving when I first thought there was an issue, that led me to do the leake down test pre-rebuild.
• It occasionally hesitated or did not engage smoothly when shifting into gear which I assume is just throttle linkage adjustment that is due...
• Now on my second attempt to get on plane and this time with 4 other people in the boat unlike the first atempt (just me in boat); I heard a concerning noise and immediately backed off.
• Temperature remained around 158°F, oil pressure stayed normal throughout all my outing, and there was no visible smoke or leaking.

I am not trying to criticize the mechanic. I am trying to understand what is reasonably normal after a rebuild and what should be considered a warning sign.

Would you operate the boat again, or have it independently inspected before placing it under additional load? What should be checked first: ignition timing, compression and leak-down, fuel pressure, belts and pulleys, engine alignment, scan-tool diagnostics, or the drive and coupler?

I would especially appreciate feedback from anyone with hands-on experience rebuilding or installing GM-based Volvo Penta 5.7 engines.

Personally I would check...fuel quality first, then remove the drive belt, operate briefly to see if noise goes away. Next check for correct spark plugs and gaps. While plugs are out I would certainly recheck compression ( the thought of 2 leaks just after a rebuild makes me wonder if your mechanic found the original cause for low compression ( injector leak down, etc,) or even cared enough to check for leaks, timing , throttle adjustment and noise after a rebuild...enough said there ).
If that all checks out I would then be looking at the drive unit. Good old Volvo Penta ! If you are uncomfortable with the mechanical then yes I would ASBSOLUTELY get another opinion/ diagnosis from a reputable technician.

Thank you for taking the time to read through everything and share your knowledge—I really appreciate it!!

The original leaks were from the power-steering system on one side and an oil connection on the other. The oil leak was corrected by replacing or tightening the connection and clamps. I was surprised both leaks were present during the first water test because there was evidence of them before the engine was placed under load.

My understanding is that the original low compression resulted from some form of water intrusion. The engine builder had the block for approximately five to six months. The cylinders were bored to remove the damage or etching, and a new camshaft, rollers, and other internal components were installed.

The fuel has been in the tank since the end of last season, but the boat was stored indoors in heated storage. I assumed the fuel would probably be okay, although I will top off the tank with fresh fuel to help rule that out. To my knowledge, the spark plugs, wires, and fuel injectors are also new.

The mechanic told me last night that he plans to speak with the engine builder to determine whether any of the installed components differ from the stock engine. His thought is that those changes may require different specifications or adjustments rather than using the original factory settings.

I’m going to give them a few more opportunities to diagnose and correct it, but I agree that an independent opinion may be necessary if this continues. I have already missed nearly the entire boating season, so I’m trying to balance giving them a chance to resolve it with not allowing this to drag on indefinitely.

I would consider hooking the engine up to a diagnostic tool, like a Rinda system to see if it is throwing any codes. I would also be mindful of the break in period on a new engine. I would not be running it at full throttle. You should vary the RPM`s at generally a lower speed. The new components may not seat in properly. Then change the oil again afterwards.

Thank you!!!