BF200 2003 Engine Rattle above 4000 RPM??

I just bought a 2003 Bass Boat with a 2003 Honda BF200 with 680 Hours 20" Shaft. I believe it sat for a few months and ran seafoam in the gas and filled the tank with fresh gas 89 ethonol free. Engine has been running great two hours total inbetween fishing two days but anytime I try to go above 4000RPM I get a loud rattle from the engine. As soon as I drop below 4k it goes away.

I dont know much about these motors and Im thinking its engine knock, timing off, or soemthing with the valves.

About to order a bunch of maintenace parts filters, plugs etc, and hopefully what ever else to fix the noice.

The first (and probably easiest) thing to check in the case of rattling at high rpm is the propeller. Make sure it hasn't been chipped, dented or bent before assuming there's something wrong with the powerhead.

Good luck.

I have a backup 4 blade that came with the boat. I will give that a try tomorrow on the lake. Let you know if that worked.

If the prop changeover doesn't fix the problem, your next step is to drop the lower end and check the condition of the mid-shaft bushing. On Honda 200's and 225's manufactured prior to about mid-year 2007, that bushing is prone to failing and if not addressed can eat a hole in the forward part of the lower casing.

Its was the prop. I put on the 4 blade and no more issues above 4000rpm and overall better feeling below 4000 rpm. Thanks.

Not sure whats wrong with the prop. Wondering if I can ship it out to get fixed?????

The prop hub has probably failed.

You may be able to have it repaired but, if it's a stock Honda aluminum prop, it will likely be cheaper and easier to just replace it with a new one.

Also, don't overlook chawk_man's SAGE advice about looking after that mainshaft bushing. He knows his stuff!

Letting that thing go to "failure mode" will definitely ruin your week!

I'm glad it's better for you and thanks for keeping us informed. All input here is bound to help someone else with a similar issue.

If it's a Honda stainless prop it can be refurbished for somewhere between $130 - $150, at least around here. Most marine repair shops have a relationship with refurbishers and will handle the shipping and return for you. It may take a month or more to get it back.

I make it a practice to always carry a spare prop, thrust washer, flat washer, castle nut and several cotter pins on my boat. I can't tell you how many times I've had to change it out while away from my home pier.