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Running Rough Gen5 V6 200HP

J

jgm911t

New member
I have a 2021 Chaparral 21SSI with a I/O Volvo Penta Gen5 V6 200hp motor. Have only 70 hrs. The boat was running great but about a month ago 3 teeth on one of the gears in the upper drive broke off leaving me dead in the water. Was under warrantee and Volvo replaced the whole drive unit. After repair I put it in the water and driving to my dock the engine management system started beeping once a minute. Turned it off and after beeping continuously at me for like 15 secs the beep stopped. From then on the motor starts great but runs a little rough, feel vibration in the boat at idle. Also get a slight smell of gasoline. I can take it back to the dealer but I have to pull it and drive 150 miles. Any idea what's wrong or what to check? Dealer claims he did nothing to the engine. Thanks Jim
 
Not enough info to make a good guess

Continuous beep on newer motors can be low voltage, over heat, low oil pressure, and a few other things.

With it running fine before the drive was replaced, look around for a loose or bad connection. Bat cables to block, starter and Bat. Back by the drive, there are sensor wires that if not connected back to the drive can cause issues

The smell of fuel might be from running rough. Check all the plug wires, pull them off and look close at the ends and the plugs. One might be barely hanging on, or might have broke a plug from a Mech banging into something
 
Thanks for the input. The beeps are not from overheating or oil pressure, first thing I checked. I will check the spark plug wires and plugs, good idea. Its not running real rough but enough to notice vibration and slight gas smell. Is there an inexpensive way to read any codes?
 
Found the cause. Code reader said cylinder #5 not firing. Mechanic replaced spark plugs. They tested the boat on the water 2x's and said all is good now. However, I got it home hooked up hose and ran it, runs great at idle But ramping rpms up to 2000 rpms (no prop turning) the engine pulses +/- 50 rpms. What would cause this? Still spark plugs? Will it not be a problem under load on the water? What do you think?
 
Not recommended to run a motor on a hose that fast, the hose cannot supply enough water

It's probably the PCM doing it because it knows it's in neutral (has in gear switch). PCM has a fuel table and for that rpm injectors pulse a given amount of time. Could be the PCM is seeing something out of sync, I don't know.

If it does it running under load I would worry more about it, otherwise it's not an issue IMO
 
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