Honda Outboard BF9.9DK3 Woes

[SoggyHalyard]

Hi all, I have a Honda BF9.9DK3. Not sure what year but early 2010s I believe. I’ve been pulling my hair out and hoping someone can point me in the right direction before I decide this thing is just going to be my new boat anchor.

Here is the story:

I’m sailing in a remote region. About a six weeks ago my engine starts acting up, harder to start, stalling, needing longer to warm up and stalling on acceleration. I had not winterized it the previous year, was running year old fuel through it, and think I might have sprayed some water in vent of my fuel tank when washing my deck.

Clearly a carb issue. The issue got progressively worse and worse until I couldn’t ignore it. I disposed of my gas, cleaned the tank, got new gas, removed the carb and cleaned it the best I could. The issues still remained but changed so I figured I just was not able to sufficiently clean the carb. The issue turned to only being able to run with the choke at idle, and only being able to get to high RPM using the choke, poor idling, etc. After a few more carb cleanings the engine was idling again and could go to high RPMs with the choke to accelerate so clearly something was wrong with the accelerator jet. I ended up removing the little ball and snap ring at the bottom of the accelerator pump in addition to another cleaning. This fixed the issue and the engine was running well but noticeably rich. Smoke, smell, etc. I was only going to run it like this for a week or so until I got to a parts store but things got worse again.

Finally I got to land. I replaced the carb, new gaskets, new spark plugs (which were heavily fouled after a few hours of running rich). Got new fuel and installed a racor fuel water gasoline separator with 10 micron filter, new fuel line and bulb; did an oil change, replaced the gear oil (maybe a little low but I put it in a unmarked container so maybe not, color was okay), sprayed the whole engine down with T9, ran it on the stand in neutral and it ran great and idled well. Sweet, although there seems to be a little smoke coming from the lower exhaust, okay… maybe spraying T9 on everything was not a great idea and it’s burning off.

I put it back on my dinghy. Idle is good, maybe shy of perfect but it’s not stalling. Low speed is good. There is definitely smoke but it’s not a lot and not overly rich smelling. Big problem is the engine will not reach high RPMs. It stutters a little at about 60% WOT and then continues at any throttle over 60% like I’m sitting at 40% throttle (in terms of RPM sound and thrust).

I don’t think it’s a spun prop because the engine is not running that hard. I thought maybe fuel pump but pumping the bulb while running doesn’t make a difference. The condition seems stable to. I’ve ran it for maybe 20 minutes trying different things here and there and nothing is changing. The fuel being run through is the fuel recently purchased with Heet added.

Can some one give me some pointers on what to do next? This is killing me!