Honda 10 hp powerhead in Honda 8 hp frame ignition problem

foretopman

Cadet
Joined
Sep 5, 2009
Messages
9
I "rescued" an 8 hp Honda outboard, pre 97. It had been submerged in salt water and left laying on the beach for who knows how long. I got it started and it overheated instantly. I turned it off immediately and tore into it. Discovered that salt had clogged all of the cooling passages. When I attempted to disassemble the power had the nuts and bolts were so hard to remove that I ended up breaking the head. I checked out the rest of the frame and was able to get all the cooling passages clear. I bought a 10 horsepower power head. I installed it and bought all new electronics due to the fact that it was a point ignition system. The eight horsepower power head had a CDI ignition system. The only thing that was not new on the 10 horsepower was the flywheel. I checked all the wiring, all other specifications, timed it to factory specifications. It would not run. I set up a manifold to test the plugs outside of the head and I got sparks. I reinstalled the plugs into the engine and it still would not run. I removed the plugs and introduced a few drops of gasoline into the cylinders then reinstalled the plugs and it would not start. I removed the plugs sprayed starting fluid into each cylinder, reinstalled the plugs and it still would not start. I checked the magnets in the flywheel to be sure that they still had magnetic fields. They did. I then checked online to try to find out if I required a different flywheel for a point ignition system. I read across many sellers that indicated they have a flywheel for a 7,8 or 10 horsepower Honda. I noticed according to Honda, black flywheels were for the point ignition system, and red flywheels that indicated they were for the CDI ignition system. The flywheel that that was with the eight horsepower frame was black. I have checked and rechecked all the wiring, checked and rechecked all the specifications for the different parts that are on the power head. Does anybody have any information for me at all? Any good guess's? The number on the power head is B 100 -1000 -820, the Honda frame number is BACL 1000542 (mfg 1987), and is commonly known as a BF8A. I have found that the only difference between and seven and eight or 10 horsepower is the cam.
Thanks in advance for any help that anyone can get me, I am at my wit's end.
 
Last edited:

RCO

Petty Officer 1st Class
Joined
Jun 15, 2016
Messages
350
Check spark with an open air spark tester. It should be able to jump 3/8" or more. Check for a sheared or missing flywheel key if spark is present and able to bridge that gap. If that is ok check the timing with a timing light. Doesn't need to be exact, but should be close to TDC when firing.
 

Mohawkmtrs

Chief Petty Officer
Joined
Jan 13, 2010
Messages
561
After doing what RCO says, install new, proper spark plugs...ask me why.
 
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