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Honda BF25A

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WalleyeDude

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I have an unusual problem with my 25 Honda and I'm hoping that Honda Dude can help. On cold starts only, engine starts immediately and runs very well for 2 minutes (120 seconds exactly) then RPM drops down and the engine starts to sputter for 1 minute (60 seconds) and during that 1 minute by pulling the choke or giving it gas the RPM will not go up. At the end of 1 minute the RPM go up and it stops sputtering and it runs great until the next cold start. This motor is 10 years old and has been very well maintained. Sure hope you can help.
 
Sounds like it`s your thermostat that`s starting to open which will drop your revs as cold water is starting to be passed through the engine. Once it settles itself out then the revs will pick back up.
 
mattspeed.triple is may be on to something. Thermostat may be stuck open.

What is the serial number? There are a couple of different designs of the 25 carburetors.
Sorry for any typos....my computer drive crapped out on me and I am using my phone.

Mike
 
Thanks Matt and Mike; really appreciate your suggestion. The serial number is BAJL1005531. Let me know what else you think. Thanks again .....Gene (WalleyeDude)
 
You have one of the original 25's. Nothing real complex with the carburetors.

If could be the combination of the thermostat, extremely cold weather, and/or fuel.

You might consider dumping the fuel into your car and getting a fresh tank of fuel.

Flush the carburetors and see what happens.

Be sure to use a good fuel treatment like stabil-marine or pri-g.

Mike
 
Thanks Mike and Matt; I think the thermostat suggestion is a good one and I'll be replacing it as soon as spring arrives and I get the boat out of storage. Thanks again and I'll keep you posted in case anyone else has this problem.
Gene
 
Not a problem Gene and hopefully it`ll help.

I`ve just ordered a couple of replacement thermostats from the states as here in the uk parts cost a fortune. I own a bf25 as well as several other honda outboards and i find it the be the hardest to get running smoothly.

Anyway, let us know how you get on and we`ll help if we can.

Matt.
 
Thanks again Matt; I'll also be ordering a new thermostat shortly and putting it on as soon as I get my boat out of storage. We're have a very cold winter in Canada this year.
Have a great day and we'll keep you posted when the weather breaks. ..............Gene
 
Hi Hondadude and Matt. I think you fellows hit it dead on as far as fixing the problem. I've installed a brand new thermostat as per your suggestion and I have ran the motor in my driveway on a water supply hose; the problem seems to be corrected. I haven't put the boat in the water yet but as soon as I do I'll report further. Your suggestion was much appreciated; thank you and have a great summer
Gene WalleyeDude
 
Matt and Honda Dude; I've had the boat out on the lake a couple of times and my problem is fixed; thanks for sharing your knowledge and your advice ; you guys are great! Have a great summer on the water.
Thanks again, Gene
 
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