Hello all-
A year ago I bought a used BF45A with controls for a screaming deal of $650 to run on my 15' Glasspar runabout. It has been a really good motor until this problem-
I overheated it running on the flusher, the impeller bit the dust. I was busy washing down the boat and did not notice the tell tale wasn't putting out water until the exhaust sound changed. I shut it down, but it was pretty hot to the touch.
I pulled the foot, and installed a new water pump kit complete as my wear plate was grooved up. I reasembled, it ran and pumped well on the muffs.
I took the boat out and ran 10 min below 2000 RPM, then got it on plane and ran up to cruise. After two to three minutes, the horn went off, and heavy steam came from the exhaust idle port. I thottled back to under 2000 and the horn quit. I idled back in. None of my lights on the control (Honda side mount) lit at the time, I later found they do not work when tested per the Honda service manual.
I later tested the temp switch and the oil switch, they both function to set the horn. I pulled the thermostat housing, the 'stat was very corroded and broke in my hand. The plunger so to speak was stuck- I figured the thermostat was stuck just barely open and did not open enough to deliver the volume of water at higher speeds/loads. I replaced the 'stat and gasket.
Took the boat out this afternoon, same thing, 2-3 minutes on plane, got the horn and the steam cometh. Idled back in.
Did a compression test at home- first off. the bottom plug is whitish, the other two are sooty. Compression with the throttles closed (yeah, I know the book said to unhook the linkage etc) was 115-120-115 psi. Even enough for me.
My guess is a warped head causing a blown gasket, and until the thermostat opens it does not effect it. No evidence of water is found in the oil.
I have experience on two stroke outboards, and am a marine tech by trade on inboard diesels, but have not touched on OHC four stroke outboard yet.
Anyone agree on the head gasket diagnosis, and have any advice on pulling the head, tips-tricks?
Eric in Savannah
A year ago I bought a used BF45A with controls for a screaming deal of $650 to run on my 15' Glasspar runabout. It has been a really good motor until this problem-
I overheated it running on the flusher, the impeller bit the dust. I was busy washing down the boat and did not notice the tell tale wasn't putting out water until the exhaust sound changed. I shut it down, but it was pretty hot to the touch.
I pulled the foot, and installed a new water pump kit complete as my wear plate was grooved up. I reasembled, it ran and pumped well on the muffs.
I took the boat out and ran 10 min below 2000 RPM, then got it on plane and ran up to cruise. After two to three minutes, the horn went off, and heavy steam came from the exhaust idle port. I thottled back to under 2000 and the horn quit. I idled back in. None of my lights on the control (Honda side mount) lit at the time, I later found they do not work when tested per the Honda service manual.
I later tested the temp switch and the oil switch, they both function to set the horn. I pulled the thermostat housing, the 'stat was very corroded and broke in my hand. The plunger so to speak was stuck- I figured the thermostat was stuck just barely open and did not open enough to deliver the volume of water at higher speeds/loads. I replaced the 'stat and gasket.
Took the boat out this afternoon, same thing, 2-3 minutes on plane, got the horn and the steam cometh. Idled back in.
Did a compression test at home- first off. the bottom plug is whitish, the other two are sooty. Compression with the throttles closed (yeah, I know the book said to unhook the linkage etc) was 115-120-115 psi. Even enough for me.
My guess is a warped head causing a blown gasket, and until the thermostat opens it does not effect it. No evidence of water is found in the oil.
I have experience on two stroke outboards, and am a marine tech by trade on inboard diesels, but have not touched on OHC four stroke outboard yet.
Anyone agree on the head gasket diagnosis, and have any advice on pulling the head, tips-tricks?
Eric in Savannah