Honda BF20 4stroke stalls when idle or low rpm

[azzurro]

Hello!

I'm starting the boating season but it seems I have a bad winterized outboard.
Model is Honda BF20 4 stroke year 2010 manual start. No more than 30 hours. Last summer it started on first pull and worked fine.

It is hard to start and only with choke on. When choking off, engine stalls, even after 10 minutes. Tried to choke off slowly but stalls. Even choked on after some minutes, when geared forward the engine stalls. If I open throttle it will push the boat but not smoothly, sort of pulls.
I've changed both spark plugs but same problem.
I'm afraid I'll have to get the carb cleaned... any clues before doing that?

Thanks!

 

[azzurro]

Re: Honda BF20 4stroke stalls when idle or low rpm

Hello!

I'm starting the boating season but it seems I have a bad winterized outboard.
Model is Honda BF20 4 stroke year 2010 manual start. No more than 30 hours. Last summer it started on first pull and worked fine.

It is hard to start and only with choke on. When choking off, engine stalls, even after 10 minutes. Tried to choke off slowly but stalls. Even choked on after some minutes, when geared forward the engine stalls. If I open throttle it will push the boat but not smoothly, sort of pulls.
I've changed both spark plugs but same problem.
I'm afraid I'll have to get the carb cleaned... any clues before doing that?

Thanks!

Hi all:

I must say it's a BF20D (with Starter Enrichment).

 

[isaksp00]

Re: Honda BF20 4stroke stalls when idle or low rpm

Similar problem with my Honda 8HP BF8A was caused by clogged low speed (idle or pilot) jet. I don't know if the 20 has the same general carb design, but if it does, that jet can be removed from the carb body without removing the carb from the engine.

 

[azzurro]

Re: Honda BF20 4stroke stalls when idle or low rpm

Fixed!

- Start on choke (not so easy!)
- Slowly take to wide open throttle (not so easy, it stalled several times).
- 30 seconds there and then push choke! Stay there 30 secs.
- Slowly close throttle, until you have it running on idle.

Then I get it there, ocassionally opening throttle. I tested many times it before going for a ride (warm start, cold start, idle, WOT, etc.). Now it works as it used to be.

Now I will explain why it happened (PLEASE, A HONDA GURU TO CHECK! I'm not an expert and may be wrong).
1 - Toooooo much fogging oil in the air intake
2 - "Starter enrichment" feature from Honda BF20D engines (and all of the small Honda engines with a "D").
The "choke" in these engines is not a traditional choke. Instead, it makes the fuel pump to push both air and fuel. This allows the engine to start on choke, even if the air intake is blocked: but as the main air intake is blocked, the engine "hesitates".
When on high rpm, the cylinders sucked the oil and cleaned the air intake.
3 - (And probably the main cause): my first winterizening and awakening a winterized engine.


Although I do not need it now, I will get a carb cleaner spray. It's the worth trying it before having the engine serviced during my holidays.

 

[mcjsarf1]

Re: Honda BF20 4stroke stalls when idle or low rpm

Hello!

I'm starting the boating season but it seems I have a bad winterized outboard.
Model is Honda BF20 4 stroke year 2010 manual start. No more than 30 hours. Last summer it started on first pull and worked fine.

It is hard to start and only with choke on. When choking off, engine stalls, even after 10 minutes. Tried to choke off slowly but stalls. Even choked on after some minutes, when geared forward the engine stalls. If I open throttle it will push the boat but not smoothly, sort of pulls.
I've changed both spark plugs but same problem.
I'm afraid I'll have to get the carb cleaned... any clues before doing that?

Thanks!

I have two BF20's and when running the fuel out of one of them, I got out of the boat and the motor came out of the water and I did not notice it. I heard the exhaust get loud, but did not get back in to shut it off in time. After that, I had similar shut down problems after trolling for ten minutes or so. It turned out to be a scored plate in the water pump that was restriciting the ability to pump enough water to keep the unit cool, so it would slightly heat up and the computer would shut it down. It took two trips to the shop to figure it out. They replaced the plate in the water pump and installed a new impeller and the problem went away. I could see the impeller marks on the plate when I picked up the motor.

The shop guy was telling me of problems with a plugged port in the carb that will cause starting problems. My other unit would not run smooth when starting, yet never shut down. I think that some Sea Foam in the fall would have helped me. With today's no-lead ethanol mixed fuel, a guy has to be careful as it will screw up the fuel system. One of my snowmobiles was not run for two years, and the carburator siezed up because of the ethanol. $400 repair bill! I have since switched to 93 octane for all my four-stroke outboards (4 of them) and other small engines.

Good Luck!

Mississippi River Mike