Honda BF 15 Rough Idle

[mchech]

Also has a black soot like deposit coming from the exhaust vent immediately below the engine cover. Motor runs ok at higher throttle. This is the second time in 2 years this motor has been back to the dealer for this problem. First time they blamed it on the fuel quality so they cleaned the carb and it seemed ok....But I treat every drop of gasoline this motor has seen with Sta-Bil regardless of the season. They blamed it on Sta-Bil not doing its job and recomended their own brand. I refused to use anything but Sta-Bil since it is readily available and recomended in my Honda owners manual. It never sees gasoline older than 3 weeks. It has been winterized according to the book. Flushed, fogged, carb drained, 3 gal. tank drained and even fuel hose drained. This time one mechanic blamed my winterization technique. I blame it on them not solving the problem the first time. Supposedly the dealer wants to replace the thermostat. I understand these motors are temperature sensitive. Are we on the right course to restore this motor's reliability? Am I feeding this engine properly?

 

[ebtide]

Re: Honda BF 15 Rough Idle

I am a new Honda owner and new to this post. However, i just bought a 10 hp that would not idle. It started fine at high speeds, but no idle. The previous owner had the carb cleaned out with no luck. I found that bugs had cloged the carb vent line. Since the carb vent line is next to the water outlet, i checked that and found it plugged as well. Unfortunately, the water blockage went all the way into the block and i had to take off the water cooling jacket on the left side (facing the prop) of the engine. I actually had to use a chisel and hammer to get that blockage clear. I also found the thermostat very corroded. The water cooling jacket outlet and carb vent lines are only 1/8" so it doesn't take much to cause a problem.

 

[gss036]

Re: Honda BF 15 Rough Idle

I think that Sta-Bil is designed mainly for fuel stablization, not a carb cleaner. Try a can of SeaFoam or Chevron Techron Fuel injector cleaner in your gas. That may clean out any junk that has collected. The Hondas have very small orfices and clog easily. I have been running my 15hp Honda since about 1994-95 and never had any problem, but again I do use SeaFoam in my gas when I decarb my 200 Merc 2 stroker and also run some of the mixture into the Honda since both have the same gas fittings.<br />There are idle adjustment screws on the carb that you can adjust and also a drain screw to drain out the carb fuel bowl.<br />As far as the thermostat is concerned, if you have the orginal one still in the motor, I would buy a hotter model and install it yourself, very simple job. They do like to clog up with salt and plug water flow. If you monitor your oil closely, you may find that it makes oil, that is because it is running cold and letting unburned gas get past the rings into the oil.

 

[mchech]

Re: Honda BF 15 Rough Idle

The motor is still under warranty so I will let the dealer handle the thermostat and cooling. I have read up some on Sea Foam I will make the switch. Though Sta-Bil advertizes it stabilizes fuel and cleans systems, Sea Foam's primary purpose seems to be cleaning fuel systems and stabilizing as a secondard benefit. If I could get a few peacefull days in trolling I'd feed the Honda Old Grandad. Soon be cheaper than gasoline anyway. Thanks for the advice fellas

 

[donaldsmith_11]

Re: Honda BF 15 Rough Idle

Hi. I have the same problem (soot, vibration) on my BF15 extra-long shaft for sailboats. So far they have blamed it on my boat, on the long shaft, on excessive idling (which I don't do, I cruise for hours at a time at decent throttle)etc. etc. Meanwhile, they changed the 3 bushings to 28-HP ones and found wear on my original bushings after only 100 hours of use due to the vibration.<br /><br />My lower plug fouls after a few hours, while the upper plug stays perfect indefinitely. Does yours do this? The dealer has tested the engine and says compression is equal, so he is performing a "leak down" test to see if there is any kind of leak that a compression test would not pick up. They also ordered a new thermostat per your ideas, but they said there was no choice as to thermostat temp rating. A thermostat that was stuck partly open would explain it as the lower cylinder gets the cooling water first. They said it could not be a carb issue because the two plugs were so unequally used.<br /><br />I would be interested to hear if you had lower plug fouling and if and how the dealer has resolved your complaints.

 

[mchech]

Re: Honda BF 15 Rough Idle

I stopped by to see my dealer-mechanic to discuss a solution to the problem. He seems to think it is temperature related problem and ordered a new thermostat. He says he will clean the carb and install the thermostat next week. He said they will do it under warranty. If he would have suggested I have been feeding this motor bad gas I would have gone ballistic. Around the house I have 12 other gasoline engines that survive trouble free on the fuel I syphon out of this motor to prevent feeding this thing stale gas.<br /><br />I havent checked the plugs but I will do that tomorrow and let you know. My reason for buying this Honda was for a reliable smooth trolling motor as so many folks bragged it to be. So I spent the extra money to get the quality and I expect nothing less. My motor never trolls longer than 45 minutes followed by a upwind run at full throttle to make another pass.My thoughts are it's a 4 stroke engine and should idle for as long as it takes without any problem.<br /><br />I will share the results of the repairs as soon as they are complete

 

[mchech]

Re: Honda BF 15 Rough Idle

Just an update on the Honda problem. I traded it on 2 Tohatsus. Dealer gave me a good deal on a new 50 TLDI and a new 9.8 hp 4 stroke. Hopefully with some of the advice I have received here these motors will serve me well. Thanks for your replies.