Having problems with our Honda 90 four stroke outboard fitted to our Dive Club Rib.
The engine is about 1997, Identifier number is BBBL 1008759 on the transom bracket. BBBE 101 1579 is stamped in the block.
Basically we had a problem of salt water contaminating the fuel and discovered the fuel tank was compromised. We now have completely new fuel tanks, fuel lines, priming bulb, water separator/filter. Replaced the Honda fuel connector plugs A & B on engine, two new fuel pumps fiied, carburettors and jets removed and cleaned and replaced. New manifold gasket fitted. Carbs set up and balanced. The engine now readily starts and revs easily to red line & beyond. However, we have an intermittent misfire - more constant than intermittent! New spark plugs fitted.
I’ve checked the cylinder compressions and although a little down on the service manuals 213 PSI the four cylinders are all approximately equal (within 10 PSI) so I don’t think theres a problem with compression.
After allowing the engine to warm we removed each high tension lead in turn in order to identify the source of the misfire.
The removal of the high tension leads from plugs 1 and 4 caused the engine to practically stall, indicating these were working correctly as when replaced the engine picked up again.
However when removing the HT leads from 2 and 3 there was a negligible or no drop in rpm.
There are two ignition coils fitted. Coil 1 serves cylinders 1 and 4, while coil 2 serves cylinders 2 and 3.
Was coil 2 defective? We switched the coils and HT leads so coil 2 served cylinders 1 and 4, while coil 1 serves 2 and 3 and performed the same test.
The results were the same; removal of the HT leads from plugs 1 and 4 caused the engine to practically stall while from 2 and 3 had little or nil effect indicating the coils and leads are OK.
Checked the coils primary side resistance of both coils which is within tolerance of 0.35 to 0.43 ohms.
With the spark plug caps installed checked the secondary resistance of both coils and HT lead sets. Again this is within tolerance of 23.1 to 34.7 K ohms. This indicates the defect is not in the coils or HT leads.
Checked and cleaned the pulser coil terminals. Also tested the resistance between the two pulser units. Both are within tolerance of 168 to 252 ohms.
Removed the CDI unit and tested resistances across the 18 terminals. There are a large number of incorrect resistance readings according to the Honda owner workshop and repair manual. Many of the readings are showing infinity whereas the manual gives a tolerance range. To me this indicates the CDI unit is defective.
Now here’s the beef. A colleague been told by a service engineer friend to forget the readings as the manual is wrong and the data isn’t published anymore on newer service manuals? Furthermore he said the CDI unit is normally bomb proof!
With this in mind and the fact a new unit is over £500 any suggestions as to what to do next…… Constructive suggestions please?
Nigel
The engine is about 1997, Identifier number is BBBL 1008759 on the transom bracket. BBBE 101 1579 is stamped in the block.
Basically we had a problem of salt water contaminating the fuel and discovered the fuel tank was compromised. We now have completely new fuel tanks, fuel lines, priming bulb, water separator/filter. Replaced the Honda fuel connector plugs A & B on engine, two new fuel pumps fiied, carburettors and jets removed and cleaned and replaced. New manifold gasket fitted. Carbs set up and balanced. The engine now readily starts and revs easily to red line & beyond. However, we have an intermittent misfire - more constant than intermittent! New spark plugs fitted.
I’ve checked the cylinder compressions and although a little down on the service manuals 213 PSI the four cylinders are all approximately equal (within 10 PSI) so I don’t think theres a problem with compression.
After allowing the engine to warm we removed each high tension lead in turn in order to identify the source of the misfire.
The removal of the high tension leads from plugs 1 and 4 caused the engine to practically stall, indicating these were working correctly as when replaced the engine picked up again.
However when removing the HT leads from 2 and 3 there was a negligible or no drop in rpm.
There are two ignition coils fitted. Coil 1 serves cylinders 1 and 4, while coil 2 serves cylinders 2 and 3.
Was coil 2 defective? We switched the coils and HT leads so coil 2 served cylinders 1 and 4, while coil 1 serves 2 and 3 and performed the same test.
The results were the same; removal of the HT leads from plugs 1 and 4 caused the engine to practically stall while from 2 and 3 had little or nil effect indicating the coils and leads are OK.
Checked the coils primary side resistance of both coils which is within tolerance of 0.35 to 0.43 ohms.
With the spark plug caps installed checked the secondary resistance of both coils and HT lead sets. Again this is within tolerance of 23.1 to 34.7 K ohms. This indicates the defect is not in the coils or HT leads.
Checked and cleaned the pulser coil terminals. Also tested the resistance between the two pulser units. Both are within tolerance of 168 to 252 ohms.
Removed the CDI unit and tested resistances across the 18 terminals. There are a large number of incorrect resistance readings according to the Honda owner workshop and repair manual. Many of the readings are showing infinity whereas the manual gives a tolerance range. To me this indicates the CDI unit is defective.
Now here’s the beef. A colleague been told by a service engineer friend to forget the readings as the manual is wrong and the data isn’t published anymore on newer service manuals? Furthermore he said the CDI unit is normally bomb proof!
With this in mind and the fact a new unit is over £500 any suggestions as to what to do next…… Constructive suggestions please?
Nigel