Running different RPM's and rattle at idle speed

[Jeffthomas6ft7]

Hey everyone. I've got my starboard engine running almost 1000 RPM's higher than port engine. Also notice a loose sounding rattle while at idle speed. Any ideas? just test drove the boat today its a 2003 SR230 in lake, glass smooth conditions. Only saw about 35mph when port engine was at almost 10,000 rpms and starboard closer to 8700???

The boat hasent been used much, could it be bad gas? A fouled spark plug? Hope its nothing too crazy...

 

[B0at1n]

Possible it’s the main bearing on the pump. Those that had failures have said it sounds like shaking a can of pennies.

 

[Whiskey]

I thought that it was normal for the pumps to rattle at idle. Is that not true?

 

[scot71]

My '04 SX230, I've owned it for 5 years, has always had that rattle noise. I have always assumed it was normal for the MR-1 engines. Also, I would definitely change out the plugs. The MR-1s are very finicky when it comes to spark plugs.

 

[Gym]

I agree with @scot71 about changing plugs. It could be a number of things like low compression, dirty injectors or even throttle cable not adjusted properly. You want to start with the simple stuff first. Anybody who buys a used boat should do a plug. oil & filter change first thing. We've had many questions/problems on this forum from members that loaded up their "new to them" boat with friends/family and went for their first trip only to find out something wasn't working.