Welcome to the Forum!
The slight surge around 4000 rpm +/- is typical for these engines - it is the V-TEC system (variable timing) trying to figure out which mode it should be in. During a sustained run, it will usually settle down, eventually.
Get your owners manual and follow the maintenance schedule in there. If you don't have one, you can download it from
http://marine.honda.com/support. If you are really curious and/or want to do more of your own maintenance, troubleshooting, and repairs, invest in the official Helm Shop Manual which you can purchase from off of Amazon or eBay - it's about $116. Do not waste your money on any of the aftermarket manuals - too many errors and omissions.
Yes, do change out both the HP and LP fuel filters AND drain the VST.
That engine may or may not have the old exhaust tubes, which allow water to get up into the exhaust tubes and blow the HO2 sensor. That is covered in Honda Service Bulleting 56. Send me an e-mail at
[email protected], and I will send you a copy so you can check your engine's SN against the list of ones with the old-style exhaust tubes. Honda sells a complete kit for doing the job.
Yes, play with the prop - these engines perform best when the rpm's at WOT are in the 5800 to 6000 range.
When you change plugs, use ONLY NGK IZFR6F11
As for the mid-shaft bushing, I do not know how you can determine whether you have the old style case or the new one which allows more water in to lubricate the bearing. Others on this forum may know. However, every time you drop the lower leg to change the impeller, you can look up inside the leg and see the bushing. Test for looseness and corrosion.
Learn to pull your own fault codes if you get an alarm. Take off the engine cover and the plastic cover over the electronics on the front of the engine. There you will see a red four-pronged female plug. Use a paper clip to shunt the lime green/white wire to the black wire – that is, the two wires that are closest to the engine when the red service connector is correctly set in its holder. If in doubt, invest in a SCS service connector, which you can order online - part number 070PZ-ZY30100. For the complete procedure, send an e-mail to me and I will return the write up I did and a copy of the fault codes from the Helm manual.
Following are some lessons learned in maintaining my own BF 225...
1. The very best thing you can do for your engine is run it as often as you can. The more its run, the better it performs.
2. At every 100 hour maintenance remove and inspect the plugs. Over time the plugs have a tendency to get stuck in the head and cannot be easily removed. Before re-installing, lightly coat the threads with a heat resistant marine grease.
3. When you change oil at every 100 hours, always replace the filter, unlike the 200 hour oil filter change Honda recommends.
4. Change the water pump impeller every 200 hours, especially if operating in saltwater or shallow water conditions. Actually, I usually replace the whole water pump – it’s not much more expensive and it assures I’m getting maximum cooling because I’m not dealing with wear on the pump sides.
5. Make sure that you have a Racor or similar filter fuel/water separator in the gas line before the pump up bulb - that does a lot to keep your onboard fuel/water separator and fuel filters clean and trouble free.
6. Use an additive in your fuel to prevent phase separation of the ethanol laced gas. - better yet, use non-ethanol gas if you can find it, but still use a stabilizer.
7. If you are doing a lot of trolling or low-speed futzing around, use a decarbonizer/cleaner in your fuel, like YamaLube Ring Free.
If maintained properly and run often, you can get thousands of hours out of these engines.
