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BF5 only runs at WOT - help please

J

JEH

New member
I have a 2003 BF5 I bought 8 months ago for my sailboat. The previous owner purchased it new. He says (and I do believe him) that he only ran non-oxygenated fuel in it and ran the carb out of fuel on every use. The motor ran fine for me until this past weekend. On that date, it started fine and ran as normal when I left my dock. After a day of sailing, I started the motor and found that it would only operate at wide open throttle - it then quit altogether before I made it back to my dock (but that's another story). I replaced the plug and the fuel filter and put fresh gas in the tank. It now cranks right up but still will only run at WOT.

I suspect the next step should be a thorough carb cleaning although I wonder why it would need that if the fuel has been completely run out of the carb after each use? Is a carb cleaning the right next step? If this is not the problem, what is the likely cause? Thanks for any thoughts on this.
 
Have sailed on a Capri 25 with a 5 HP Honda.-------Cleaning the carburetor is the next logical step.----There are some very small passages that can plug up.---That usually can be done without new parts needed.---------Perhaps check valve clearance too.--------Has a new impeller ever been installed ??
 
racerone said:
Have sailed on a Capri 25 with a 5 HP Honda.-------Cleaning the carburetor is the next logical step.----There are some very small passages that can plug up.---That usually can be done without new parts needed.---------Perhaps check valve clearance too.--------Has a new impeller ever been installed ??
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Thanks racerone. I have not replaced the impeller and do not know when that was last done. I did not think that was a likely source of the problem - am I mistaken about that? Thanks again for your helpful info.
 
Impellers are routine maintenance that must be done. ------Also inspect the thermostat.----Motor must warm up for proper idling.
 
racerone said:
Impellers are routine maintenance that must be done. ------Also inspect the thermostat.----Motor must warm up for proper idling.
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Thanks. I'm relatively new to boats - have spent most of my time with cars and bikes - so have much to learn.
 
The carb may have been run out but maybe it was not drained. It will leave a little fuel to dry up and accumulate over time.

If the engine dies like you are push the stop switch at a point as you slow it down, the carb is probably clogged in the idle circuit.

Sometimes you can get lucky by removing the slow speed jet #28 http://www.boats.net/parts/search/Honda/Outboard Engine/2003/BF5A3 LA /CARBURETOR/parts.html
and shooting some brake clean into the opening in the carburetor with a couple shorts blasts of compressed air. Even the compressed air in the can that you use for cleaning a computer will work. Also, make sure that the small passages in the slow speed jet are clear.

That my just take care of it.

If not, then a thorough cleaning is in order.

Mike
 
hondadude said:
The carb may have been run out but maybe it was not drained. It will leave a little fuel to dry up and accumulate over time.

If the engine dies like you are push the stop switch at a point as you slow it down, the carb is probably clogged in the idle circuit.

Sometimes you can get lucky by removing the slow speed jet #28 http://www.boats.net/parts/search/Honda/Outboard Engine/2003/BF5A3 LA /CARBURETOR/parts.html
and shooting some brake clean into the opening in the carburetor with a couple shorts blasts of compressed air. Even the compressed air in the can that you use for cleaning a computer will work. Also, make sure that the small passages in the slow speed jet are clear.

That my just take care of it.

If not, then a thorough cleaning is in order.

Mike
Click to expand...

Thanks, Mike. I appreciate the input. I've got a spray can of carb cleaner I use on my bikes - I will give that a shot.
 
If you do get it running with the carb cleaner, don't ignore racerone's advice about the impeller maintenance. VERY IMPORTANT.
Also, it could have a stuck float and running it at WOT would be the only way it would want to burn that much fuel. Sometimes spraying into the float bowl with the drain screw removed will unstick a float. BUT these are usually temporary measures and it is likely to happen again if there are deposits in the carb.
Good luck.
 
Yes ! If you do a few regular chores...thermostat and pump impeller being at the top of the list if you don't know when they were last done...these outboards will run forever.
While the shop manuals from HELM INC. are the best and are pretty thorough (only one I recommend), they aren't very useful when it comes to cleaning/rebuilding the carburetor. Honda has a dedicated carb manual that is excellent though and only runs around $40 tax and shipping included.
If Honda offers a "kit" for your water pump, buy it instead of just the impeller by itself. The kits are very cost effective and you'll get superior reliability and performance from the pump if all the related parts are refreshed.
 
Many thanks - this is a great forum and I appreciate all the helpful advice.

Do you recommend the HELM manual over the Honda shop manual? I was about to buy the Honda manual but perhaps I should rethink that? Thanks again
 
The Helm manual IS the OFFICIAL Honda shop manual. Stay away from Clymer, Seloc, Haynes or any others that list many different model coverage.
 
Yes! THANKS hondadude!
I don't know why I seem to have so much trouble finding and sharing those service manual links but at least you were ON IT, Mike, and took care of our new friend:)
 
Guys - just wanted to report back on my progress. Unfortunately, I had the flu so got a little behind. Anyway, I cleaned the carb and put in a new fuel filter after which it fired off on the second pull - it now revs and idles like a new motor. Thanks to all for the advice.
 
Awrright! Good to hear of your success! Now, you can pass on your knowledge "of experience" with others that have the same Honda. Thanks for the update and don't forget to keep that carb DRAINED before putting her up for a time.
 
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