Honda bf90a Issue

[Dougie90]

Hi, I have a 2005 BF90A, the engine lay for 7 years.
I have it going this year, before going, replaced oils, filters , spark plugs, thermostat, an impeller kit and carb kit. The engine runs smooth, although, power comes and goes.
carbs are clean. Running off a portable tank with an additional fuel filter, all fuel going is as clean as can be.. carbs have been cleaned since also.
the engine will come and go with the power, you’ll get maybe 20 mins of going well and all of a sudden she won’t rev past 3500rpm and do no more than 9.5 knots, then turn her off for 5/10 mins , she will rev out and do 20 knots no problem, but only for a short time.

would anyone have any knowledge or information that may point me in the right direction?

im learning as I’m going any help would be much appreciated

thanks

 

[Alan Hicks]

If this is a salt water motor, my bet is it's getting hot. Why it's getting hot can be difficult to figure out.

You say you replaced the impeller "kit". This is an issue that's caused some issues (installing a kit vs. replacing all of the pump components).

 

[jgmo]

Hi,

No alarm or warning lamp?

I don't have any experience with this outboard but, like Alan, I thought it might definitely be cooling system related since it seems like it's going into limp mode on you.

I just chimed in because when I was looking up info on the engine, the parts diagram shows this engine as having two pressure relief valves.
See item 4 in the link below.

https://www.boats.net/catalog/honda...a-vin-bbbl-4700001-to-bbbl-4799999/thermostat

I have recently read about other guys finding issues with water pressure relief valves that seemed to cause symptoms similar to what you're experiencing. Again, no personal experience with those or the 90hp but I just wanted to point out what might be something for you to check out.

You might find one or more of those cases by searching the archives as I don't remember all the particulars. I do seem to recall that one case was on a 150hp though.

Good luck.

 

[iang6766]

Not limp, on these motors limp is a very rough idle. Perhaps dropping a cylinder due to a faulty ignition coil, try a cylinder drop test when the revs are reduced