Honda B100 - Year, Spark Plug and Parts Question

[pckeen]

I picked up this motor last year, and it ran poorly - seemed to be starving for gas. I've cleaned the carb and the fuel pump - there was a lot of varnish in the carb, and the fuel pump flushed out a lot of yellow crud. Compression is good.

So three questions.
1) The serial number is B100-101279C. Would this be a 1979 motor?
2) The spark plugs simply had the screw thread where the boot ties into it, but looking inside the boot, the boot looks larger than the screw head (although the boot fit on tightly). When I replace the plugs, should I be leaving the tip on?
3) Anyone know where I can find a fuel pump rebuild kits? I couldn't find one on any of the usual sites, which listed the parts as obsolete.

 

[wrench 3]

Do you have a complete model number? It should start with B10 and then go into a bunch of letters.

 

[pckeen]

Do you have a complete model number? It should start with B10 and then go into a bunch of letters.

The complete model number is B100-101279C. It's a Canadian model, so it will have different model numbers than the U.S. serial numbers.

 

[wrench 3]

It should still have a similar model number. Unless all the ones I've run into up here have been American.

 

[pckeen]

I don't see any other numbers on it - on the identification plate, that's the only number there is. Is there somewhere else I should be looking?

 

[Alumarine]

On the front of the block I think there might be a number.

 

[Alumarine]

I would put the screw head on the plugs and see if the boot goes on ok.
Usually the ones that have the threads showing make a rachety noise when you put the boot off and on.
Does it have points or CDI ignition?

 

[wrench 3]

I've found the sticker with the model number on the side of the engine also.
The hard plastic Honda boots have a single straight spring wire that goes across one side of the threaded terminal.

 

[Springcrik]

The threaded caps on the spark plugs are installed on my B100 and the boots fit tightly. And it runs very well

 

[pckeen]

I would put the screw head on the plugs and see if the boot goes on ok.
Usually the ones that have the threads showing make a rachety noise when you put the boot off and on.
Does it have points or CDI ignition?

CDI

 

[Alumarine]

I just checked my 1981 BF75L 7.5 hp.
Mine has the threads exposed on the top of the spark plugs.

Here's a picture where the serial no. is on the block.
It's hard to read but it's in the middle of the picture just below where it says CM3

 

[pckeen]

On the front of the block I think there might be a number.

Long delay - doing other project. The front of the block had the same number as on the plate on the side.

 

[Alumarine]

That number doesn't quite fit into this chart but it might be a 1979.
Interesting that it says Unique for engine type.

w_w_w.hondamarine.pl/download/rok_produkcji_silnikow.pdf

 

[pckeen]

I found a replacement fuel pump, and after some tinkering with the carb float, it's running. No water is pumping, so I'll be picking up a new impeller. What do I have to disconnect to remove the lower unit? Just the four bolts or is there more?

 

[pckeen]

OK - so I worked out how to get the lower unit off - there are five bolts in the lower unit that has to be disassembled. You also have to remove the cotter pin and pin that holds the gear shift linkage off. You need to remove the silver block next to the gear shift, to access the pin. Don't drop it down the engine shaft (don't ask how I found that out). :lol:

The impeller in there looked fine, so I have removed the intake manifold and disassembled hte gasket and plate. Sure enough, the water passages in the intake manifold had a lot of debris, and what looked like bits of an old impeller in them. The water exit nozzle was completely clogged with a hard substance - I had to take a drill bit to it to clean it out. The thermostat was also clogged with bits of broken impeller, but once I removed the bits, it seemed to work.

No point putting an old thermostat back in, so I have ordered a new thermostat and new gaskets, plus a couple of bolts and spacers that I discovered damaged in the lower unit.