Spring Cleaning

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louis

New member
My Honda BF50 motor has been gradually idling worse and worse and now it started to hesitate between 1,300 rpm to 2,200 rpm.

If you have a similar problem here's what I did to clean up that mess:
1) Took out the pilot screws and clean them and reinstalled them (1 full turn after seating. Different for other motor models)
2) Replaced the spark plugs. Changed from Champion to NGK (probably not that important)
3) Replaced water/fuel filter
4) Removed the air baffle and ran Deep Creep to decarbonize till the cows came home.
5) Changed motor oil
6) Ran high concentration of sea foam in the fuel for 2 hours.

It purrrs now and have not run this quiet before.

I'm guessing that it's mainly # 1, 4 & 6. Hope it helps someone.
 
Good info, I agree on your concensus 1, 4 and 6. I have also had good luck on small dingy motors with certain 'temporary' conditions of stubbornous to remove the idle mixture screw and spray WD-40 full force into the mixture cavity using the thin plastic tube inserted fully. I wouldn't think WD-40 would hurt any of the components, but it sure does blow out any stuff that seems to accummulate in there, so far so good.
 
louis":nn3wbf98 said:
My Honda BF50 motor has been gradually idling worse and worse and now it started to hesitate between 1,300 rpm to 2,200 rpm.

If you have a similar problem here's what I did to clean up that mess:
1) Took out the pilot screws and clean them and reinstalled them (1 full turn after seating. Different for other motor models)
2) Replaced the spark plugs. Changed from Champion to NGK (probably not that important)
3) Replaced water/fuel filter
4) Removed the air baffle and ran Deep Creep to decarbonize till the cows came home.
5) Changed motor oil
6) Ran high concentration of sea foam in the fuel for 2 hours.

It purrrs now and have not run this quiet before.

I'm guessing that it's mainly # 1, 4 & 6. Hope it helps someone.
Click to expand...

Just to add a little more info...

1) Doesn't work on '98 and newer motors; they're capped for EPA requirements.

2) It does make a difference...often a big one. I only use NGK.

3) Every year. The little internal guy is not a separator, only a filter. If you're changing the fuel/water separator on the boat annually the internal engine filter will last a couple to four years (depends on climate, fuel, etc).;

4) Shouldn't be necessary at all if your thermostat works (that's a real BIGGIE) and your carbs are properly adjusted (pre-1998). I'm generally not in favor of diluting all the lubrication oil on the cylinder walls.

5) At least once a year and twice doesn't hurt if you're getting some hours on them.

6) Never, ever leave fuel in the carberators (a couple of days is fine; more than that...run them out). For storage longer than a few weeks open the drain screws at the bottom of the carbs once you've run the engine out of fuel to get rid of the last of the dregs (close them afterwards).

There are three carburetors there; just as on any multiple carb setup they should be balanced periodically (every year isn't bad; certainly every couple for sure). It's not hard to do but it takes a carb stick or multiple vacuum gauges so it's usually easier to let a dealer do this part (if you own a multiple carb motorcyle generally you're all set and you already know what to do).

Check that thermostat; it's vitally important. If it sticks open and the engine runs too cools it causes carbon buildup on the head and pistons. It also results in unburned fuel in the cylinder which the oil ring grabs and sends back to the oil sump (pan). That in turn dilutes the oil and breaks down its lubrication properties. If you've ever pulled the dipstick on your BF40 or BF50 and it seemed like there was too much oil (and it wasn't that way previously) you've got a stuck open thermostat and you're "making oil" (by adding gas!).
 
OK-here is the deal. I have a second hand Merc 75 4-stroke on a CD 22. The temperature gauge does not register a temperature. I have pulled the thermostat and it was closed at ambient temperature and opened when I put it in hot water (didn't do a careful measurement). I pulled the temperature sensor and it read about 2K ohms at ambient temp. and went down in hot water. I hooked the temp sensor back up and put it in hot water, turned on the ignition key (power on) and the temp gauge still did not read a high temp. I jumpered the temp. cable so the gauge would think it's a really high temp-still nothing. So either there is either a break in the line to the gauge (I hope not since tracing that would be really hard) or the temperature gauge is bad. Any thought on how to check the gauge and if it is bad where can I order one? :roll:
 
Hey Jon&Patty,


I get all my parts from here:
http://www.boats.net/parts/

On major purchases the price is always much lower than the dealer (sometimes by hundreds) and their really helpful over the phone to boot. I'm pretty sure they have Mercury parts.

Sounds like a bad thermostat. The chances of the thermostat going bad vs. the wire is much more likely. They don't cost much so try replacing it. If you're overheat sensor is going off I'd suggest that you run it without the thermostat (if possible) while your order is coming through the mail and make sure you run a high octane fuel to keep the deposits from forming.

It won't make much difference if you run regular gas for few days so don't fret if you have regular gas in your fuel tank.

Good luck.
 
louis, thanks for the link. I just bought o-rings for the lower end oil check & drain bolts at $2.49 each at the local Honda stealer. Boats.net has them for $.63 each!
 
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