BF5 kills after running 10 -20 min -- Suggestions?

cgerrys

Recruit
Joined
Aug 6, 2007
Messages
2
I have a pre 1989 Honda BF5 outboard -- 5hp, 1985 I think (VIN BF50L-1000958). It's on a sailboat so it only runs a handful of hours a season. I only use about 1-2 gal. gas/year. Generally it has started right off & run smooth.

Last season it started to act up: starting normally & running for a while then killing. After it did that a couple of times I changed the fuel filter and plug. As I recall, I didn't run it for long periods of time after that.

This spring, it seemed to run OK when I would use it for 5 - 10 min to get out of the marina & set sail. One day I decided to just motor along shore. After about 10 - 15 minutes it started to lose rpms & didn't respond to more throttle. Partial choking seemed to help a little but eventually it stalled. In trying to restart, I noticed the primer bulb was not even a little firm. I pumped it up & after about 5 - 10 min., including some time with the motor cover off looking for something obvious, it started. After running about 1/2 throttle for about 5 min. it stalled again. Again, pumped the primer bulb & spent some time trying to get it started, including some time drifting while "waiting in case I flooded it." When I did get it started I was able to nurse it back to the marina by giving the primer bulb a squeeze when it started to lose rpms.

Took it home & figured it was a fuel issue. Discussed it with my local non-Honda-authorized motor repair guy (who is authorized for Force/Johnson, Mercury, Briggs & a host of other small motors) and we developed a list of potential fuel trouble spots related to delivering fuel to the fuel pump or the fuel pump itself. Worked through the list and concluded the fuel was getting to the fuel pump. As part of this, I drained the carb & then was able to pump fuel into it with the primer bulb. The primer bulb will pump up & hold pressure now for 48 hours.

Decided to try & replicate my problems by running the motor in a tank but couldn't get it started. Pulled the spark plug to check it for being flooded & while I was at it, checked it for spark. Got a weak white spark. Put in a new gapped plug out of the box -- got no spark. Put the old plug back on -- got an even weaker spark than the first time.

Now I am thinking ignition. Went back to my local guy (aka "Fuzzy") & we talked about possible ignition problems with the worst case scenario the CDI module. I told Fuzzy I was in over my head & could he work on it? He's pinched for time (my lovely wife & I are scheduled for a sailing vacation in 3 weeks), has no Honda manuals, & can't reliably get parts for old Hondas. My nearest Honda dealer is 85 miles away & last time I asked him, wasn't real keen about working on 20 year old Honda outboards.

I think I have found an internet source for parts for my motor (boats.net) but I am at a loss as to how to troubleshoot from here. This is where you folks come in with suggestions.

Does it sound like an ignition problem, fuel problem, or both?
Is there a source of troubleshooting proceedure info for these problems out here in cyberland?
Is my best move to order & install a new "ignition coil assembly & hope that I get good spark?
Anybody had experience getting parts from boats.net

I am open to suggestions.

Thanks.

Gerry
 

cgerrys

Recruit
Joined
Aug 6, 2007
Messages
2
Re: BF5 kills after running 10 -20 min -- Suggestions?

Updated info:

Cleaned & regapped the old plug & double checked the new plug tonight. Put motor in semi-dark corner of garage & checked for spark. Both plugs arced a whitish-blue when giving the starter a HEALTHY pull. Makes me think maybe I can get it started.
 

lexi

Petty Officer 3rd Class
Joined
Jul 22, 2007
Messages
83
Re: BF5 kills after running 10 -20 min -- Suggestions?

Clean out the Ht plug cap with some nice soft cloth and a little alcohol. It`s the metal bits you are cleaning. Also clean the HT lead itself with a hot soapy cloth and dry out. The carb is simple to remove and clean with a can of Carb Cleaner. Use the straw provided and shoot it through the jets till you see it come out where it should.

Make sure float needle is clean and set at correct height. Is mixture screw set properly? About 1 1/4 turns out.. Idle is quite high on that motor. Use new fuel as fuel goes off if left for long periods in the heat.

If you suspect coil then you can check resistance with a meter but you will need the figures. Make sure the little dead man switch is not coming loose and giving you an intermittent connection.

Alex
 
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