bf90 stalls at 4000rpm after a while

Reds · 14 March 2012, 12:10

Hi,

I have a Honda BF90A2 that after sometime running at 4000rpm stops with fuel starvation. The primer bulb is colapsed. Normally it starts right away and does the same problem after a while. The outboard had a general maintenance 1 month ago (oils, filters, plugs, thermostat, etc).

I did some troubleshooting, and when I take out the water separator filter from the fuel circuit, the problem goes away. The filter is a Delphi 296HDF (CAV type) and is brand new.
Can you help me diagnose what is the problem? Is it possible for the filter element to be bad? the old one did the same so I installed a new element but the problem continues.

Regards,
Luis

9D280 · 14 March 2012, 12:33

How new is the setup?

I had to up my hose size when I swapped form a 30 to a 55HP. The 1/2" hose that woreked fine on the 30 wasn't big enough to feed the 55! I guess if you have a filter creating resistance as well, if it is teetering on the edge of too much "line resistance" then the difference between clean & dirty filter might be the proverbial straw?

What size is your hose? You'll need at least 3/8" for a 90.

Reds · 14 March 2012, 14:31

The setup is from 2004. I don't know the hose size, but it only started doing this one month ago when I first purged the water from the bottom of the filter.

Can it be air in the filter????

Reds · 14 March 2012, 14:36

Forgot to say that the filter element is brand new but the filter body isn't. It can be clogged in the line input and output.

matt h · 14 March 2012, 20:08

Quote:

Originally Posted by Reds

Hi,

I have a Honda BF90A2 that after sometime running at 4000rpm stops with fuel starvation. The primer bulb is colapsed. Normally it starts right away and does the same problem after a while. The outboard had a general maintenance 1 month ago (oils, filters, plugs, thermostat, etc).

I did some troubleshooting, and when I take out the water separator filter from the fuel circuit, the problem goes away. The filter is a Delphi 296HDF (CAV type) and is brand new.
Can you help me diagnose what is the problem? Is it possible for the filter element to be bad? the old one did the same so I installed a new element but the problem continues.

Regards,
Luis

The clue is the primer bulb.
Sounds like the breather is blocked on the fuel tank or the breather screw is tightened.or even the pick up in the fuel tank.. try undoing/ unblocking the breather or taking of the fuel cap when this happens and you will notice a large intake of air. good luck

Erin · 14 March 2012, 20:35

Could be two things depending on which side of the filter the primer bulb is. If the bulb is between tank and filter then it sounds most likely to be a tank related problem such as blocked breather or something partially blocking the pickup pipe. If the bulb is after the filter then it is going to be a blockage in the filter. I had something similar happen once which turned out to be some debris wedged inside the barbed inlet on the side of the filter where the fuel hose from the tank conencted on. I would suggest you undo all the fuel hose connections and check that there is nothing blocking the orifices.

Boats&Outboards · 14 March 2012, 20:39

Run it from a different external tank direct without going through any separators with fresh fuel. If it goes away start adding things back to the line until it returns. If the problem persists on the external tank....start saving

.

Peter @ Boatsandoutboards4sale ~ askboatsandoutboards4sale@sky.com ~ 07930 421007

SeaingRed · 14 March 2012, 21:36

Take the pipe off the inlet side of the fuel filter head, and hold the end of the pipe as low as you can with a container under it to catch any fuel. you should get a free flow of fuel, if not, blow down the pipe, it doesn't taste too good but should clear any blockage without splutting the tank!! If you block off any breathers and blow down the pipe you should definately get a good flow of fuel, be careful not to get a mouthful.

It's very unlikely that the new filter is duff, it sounds like an obstruction in the tank pickup. Hence the checking of free flow from the tank. I've found pick ups blocked by swarf from when the tank was made, to dead flies and spiders. Problem is worse when refuelling out of cans rather than from the pump.

Check free flow first then go from there

Reds · 15 March 2012, 23:07

Hi,

thanks to all. I bought a Honda fuel filter that is similar to the Racor filters. The outboard goes fine without the old CAV filter. I'm going to try with this new filter and then I'll let you now. I'm going to blow the breather hose and all the fuel hoses too. If that doesn't solve the problem, it's time to look inside the tank.

Thanks,
Luis

clydeoutboards · 16 March 2012, 06:48

sorry just noticed the post. If you still have problems give us a call.