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Honda BF 225 Spark Plug problem

S

Shushwap

New member
So went out to the lake on JUly long weekend..

Boat would only get up to 2500 RPM loaded, maybe 3200 rpm empty...

Tried a lot of stuff...

Anyway two plugs were not firing, so I changed those two plugs...should changed them all but time etc.

So boat works fine on the August long weekend.

But last weekend the boat would only make 3500 rpm half loaded, so it feels like another spark plug as gone...

So yes I will replace all the spark plugs with new ones.

But is there something else that might be causing the spark plugs to fail.

Unfortunately we are a 6 hour drive to the lake, and there are no honda dealers any where out there.

So any clues I can track down now will emmensely shorten the time it will take to finally resolve the issue.
 
This is new to me. What did the plugs look like? Where they physically damaged, cracked or just fouled? If they are fouled, then your engine may not be coming up to temperature and the ECM thinks they need more fuel. Also, check to be sure that your oil is not overfilled.

Just be sure to put in the NGK plugs. IZFR6F11 They are not cheap but any others may not work as well.

Mike

 
Let me emphasize the "I" in NGK IZFR6F-11. NAPA and other general parts stores will often ignore the "I" and sell you the standard NGK ZFR6H-11, which is not the correct plug for this engine. The standard NGK ZFR6H-11 has the standard circular tip, whereas the correct NGK IZFR6F-11 has a very pointed and thin iridium tip. The iridium tipped plugs cost between $16.00 and $18.00 a piece.

As a standard practice, I pull and inspect the plugs every 200 hours. If in doubt, I replace them, even though the Honda manual says they should be good for 400 hours. Also, each time you replace or re-insert the plugs, put grease on the threads. If the plugs are allowed to sit in the head for 400 hours or more without servicing, they tend to lock into the head, and that can be a BIG problem.

Pull and check your thermostats to make sure they are not stuck open. If they are, the ECM will dump in more fuel into the cylinders and that can foul the plugs.

Water in your gas can also cause this problem. Hopefully, you have an external 10 micron fuel/water separator installed. Drain it and see if you get a significant amount of water. Then inspect and drain your onboard fuel/water separator. Finally, drain the VST - you'll need a long flat blade screw driver for that, unless you want to remove the lower cowling.
 
hondadude said:
This is new to me. What did the plugs look like? Where they physically damaged, cracked or just fouled? If they are fouled, then your engine may not be coming up to temperature and the ECM thinks they need more fuel. Also, check to be sure that your oil is not overfilled.

Just be sure to put in the NGK plugs. IZFR6F11 They are not cheap but any others may not work as well.

Mike
Click to expand...


Plugs simply had a tan to brownish tinge, and of course were not firing...everything else looked fine.

Will simply change thermostats....I definately have the iridium tips and the number looks correct from memory.
 
chawk_man said:
Let me emphasize the "I" in NGK IZFR6F-11. NAPA and other general parts stores will often ignore the "I" and sell you the standard NGK ZFR6H-11, which is not the correct plug for this engine. The standard NGK ZFR6H-11 has the standard circular tip, whereas the correct NGK IZFR6F-11 has a very pointed and thin iridium tip. The iridium tipped plugs cost between $16.00 and $18.00 a piece.

As a standard practice, I pull and inspect the plugs every 200 hours. If in doubt, I replace them, even though the Honda manual says they should be good for 400 hours. Also, each time you replace or re-insert the plugs, put grease on the threads. If the plugs are allowed to sit in the head for 400 hours or more without servicing, they tend to lock into the head, and that can be a BIG problem.Just coming up on 200 hours

Pull and check your thermostats to make sure they are not stuck open. If they are, the ECM will dump in more fuel into the cylinders and that can foul the plugs.What is the correct opening/closing temp?

Water in your gas can also cause this problem. Hopefully, you have an external 10 micron fuel/water separator installed. Drain it and see if you get a significant amount of water. Then inspect and drain your onboard fuel/water separator. Finally, drain the VST - you'll need a long flat blade screw driver for that, unless you want to remove the lower cowling.
Click to expand...

Got the external fuel separator, will check the VST we did that and it was clean but the cowl has to come off to get in the last lower plug anyway.
 
Okay - keep us posted.

BTW - The brown/tan coloring is correct. It's hard to believe they still retained that color if they were not firing correctly. Could you be experiencing a restricted gas flow that is intermittent?

Just for grins, when you pull off the lower cowling to get to the plugs, open up the high pressure filter and take a look. If you can get a replacement, do so. If you have to use the old O ring, be very careful getting it back in properly. Before buttoning up the cowling, turn on the key the activate the fuel pumps and make sure that you don't have any leaks around the O ring.
 
So I finally got out there changed the plugs and the themostats....

I had a new High P fuel filter and o-ring but I could not get the screws to undo....any tips....I did blow off the fuel pressure (there was none).

I had installed two new plugs before they were white, the older plugs were quite dark brown not quite black.

I did notice a little bit of surging at 3700 RPM a search says the IAB valve maybe causing it?
 
If all is normal with the plugs, they should be light brown, almost tan. The dark brown could be due to fuel starvation. Get the HP filter changed and drain the VST.

As for the screws on the HP filter, I've never had that problem. If that filter has not been changed, that could well be your problem. Try getting some PB Blaster soaked in around the heads. Give it some time to work in, then put a screwdriver in the slot of each screw and lightly tap it with a small hammer several times. Keep repeating the process until they come loose.
 
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