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BF 75 runs fine then dies

M

mgssrs

New member
I have a Honda BF75 on my pontoon that runs fine and then will just die. The inline fuel filter will be empty and if I squeeze the primer ball I have been able to get it started again.This has been very intermittent. It might run for two different 45-minute trips and then do it again. It might run for an hour cruising around at slow speed then die. It has never done it under full power or high speed.

There's nothing in the fuel tank that I can see, the pickup tube looks good, and the screen on the end of the tube is clean. The fuel lines were all new last year and I don't see any suction leaks in the line. I replaced the inline fuel filter and the primer bulb was new last year and feels good. I am looking for any other thoughts to figure this out.
Thanks
 
Yep, that is truly an odd one.

I always try to keep in mind that NEW stands for Never Ever Worked and, with the extreme poor quality of replacement garbage we source from overseas these days, I get more suspicious of NEW as time goes by. View your recent purchases with a very critical eye.

And then there's OLD....Out Lived Dirt...
(sorry, couldn't resist making something up)

One thing I've found that can get old fast are the quick disconnects at the outboard.

The fuel hose sort of hangs there putting stress on the latch and squirming around from vibration. When I get a complaint about fuel starvation like this I usually go right to the quick disconnect and closely inspect both sides. The pin that pushes the valve open can wear down and actually be shortened to the extent that it might no longer have the "reach" to fully open the connection or it can deflect to the side because it gets "sloppy" in the fitting.

Another area is how the fuel hose lays in the boat. I like to arrange things so that the primer bulb is laying as horizontally as possible and, because of the way most are constructed internally, I like to see the flow direction arrow facing you as you look down from above.

I've seen set-ups where the bulb is left hanging vertically from the outboard in the transom well..That can cause loss of prime issues. And, I think leaving it in a "nose down" position is even worse.

Just a couple of ideas from an OLD. Hope you get it sorted soon.

Good luck.
.
 
jgmo said:
Yep, that is truly an odd one.

I always try to keep in mind that NEW stands for Never Ever Worked and, with the extreme poor quality of replacement garbage we source from overseas these days, I get more suspicious of NEW as time goes by. View your recent purchases with a very critical eye.

And then there's OLD....Out Lived Dirt...
(sorry, couldn't resist making something up)

One thing I've found that can get old fast are the quick disconnects at the outboard.

The fuel hose sort of hangs there putting stress on the latch and squirming around from vibration. When I get a complaint about fuel starvation like this I usually go right to the quick disconnect and closely inspect both sides. The pin that pushes the valve open can wear down and actually be shortened to the extent that it might no longer have the "reach" to fully open the connection or it can deflect to the side because it gets "sloppy" in the fitting.

Another area is how the fuel hose lays in the boat. I like to arrange things so that the primer bulb is laying as horizontally as possible and, because of the way most are constructed internally, I like to see the flow direction arrow facing you as you look down from above.

I've seen set-ups where the bulb is left hanging vertically from the outboard in the transom well..That can cause loss of prime issues. And, I think leaving it in a "nose down" position is even worse.

Just a couple of ideas from an OLD. Hope you get it sorted soon.

Good luck.
.
Click to expand...
Thanks for your reply. It's good to have somebody to kick around different ideas with. I don't believe there is a quick disconnect on this motor. The main gas line goes into another line and has two crimp style holes clamps on it. I have been suspicious of the primer bulb laying flat and the check valve not holding in that position. I thought about moving it to a more vertical position with the arrow pointing up just to make sure the check valve seats. But that doesn't really make much sense to me because once the motor is running the fuel pump should be pulling the fuel from the tank.
My other thought is the fuel pump. It looks like a 06167-ZY9-000 pump that is $128 so I don't want to replace it and have it not fix the problem. I can't find any rebuild kit for that fuel pump or I would try that.
Thanks again for any help.
 
Well, was thinking a carbureted model... you didn't specify. This being an FI engine that would change the thinking a little bit.

I wonder if this might have something to do with the VST inlet valve/float assembly sticking occasionally???

Not being an ex-spurt on either one I will probably still come up with the wrong answer.

I agree with you about the pump. When they fail they usually stay that way so I would not fire the parts cannon before more thought/testing.

Just for giggles, you might want to pull the vacuum line off of the fuel pressure regulator and see if it's wet or dry inside.
 
jgmo said:
Well, was thinking a carbureted model... you didn't specify. This being an FI engine that would change the thinking a little bit.

I wonder if this might have something to do with the VST inlet valve/float assembly sticking occasionally???

Not being an ex-spurt on either one I will probably still come up with the wrong answer.

I agree with you about the pump. When they fail they usually stay that way so I would not fire the parts cannon before more thought/testing.

Just for giggles, you might want to pull the vacuum line off of the fuel pressure regulator and see if it's wet or dry inside.
Click to expand...
Sorry, yes it is fuel injected. Interesting you would mention the VST float sticking. I had it in for warranty last year because it had a little erratic miss. It did not seem fuel related at all, more electrical. But the dealer replaced the fuel lines, filters, primer bulb, and added an inline filter. They flushed the system cleaned the injectors, replaced the regulator and said it was fuel related.They also charged me $1,200. When I got it back and drove it it started pouring fuel out of the vent tube on the VST. Rather than take it back to them I took it apart myself and found nothing in the needle valve or float. It was fine for a week or so then started leaking out the vent tube again. My pontoon was back in the lake and I do not have a trailer so I tried a quick fix. I pinched off the fuel line and ran it until it ran out of gas then I blew air back in the vent tube. After that it ran without leaking for the rest of the summer and so far this summer. I did this because I did not find anything in the VST when I took it apart so I expected to not find anything in it the second time either. But it is interesting that you mentioned that float because I have had trouble with it.

I'm just trying to understand this. So if the float sticks open gas will keep flowing into the VST and run out of the vent tube. If this float sticks closed it would not allow gas to get into the VST. In that case I would think it would die while running at wide open throttle not cruising at 2,000 RPMs. Also I would think that the inline fuel filter would still be full of fuel since the blockage would be at the VST but you may be on to something.
 
Ha ha...yeah, I didn't say my thought process was logical...I was just tossing it out there.
But you make very good points.

Is that in line filter like the the clear plastic little lawn mower type filters? If so, my experience with them....on Honda outboards...is that they never seem to fill with gas and can look mostly empty even when there's no problem.

Have you taken a look at the water separator? Ever drained that? Link below

Honda Outboard 75HP OEM Parts Diagram for Water Separator | Boats.net

Buy OEM Parts for Honda Outboard 75HP Water Separator Diagram
www.boats.net www.boats.net

I know those can cause problems.
 
You mentioned new fuel lines, have you checked all of the shop’s work? All it takes is a distraction of the tech. working on your engine to miss tightening up something. Vibrations and nearly tight will find a way to make life difficult.
 
jgmo said:
Ha ha...yeah, I didn't say my thought process was logical...I was just tossing it out there.
But you make very good points.

Is that in line filter like the the clear plastic little lawn mower type filters? If so, my experience with them....on Honda outboards...is that they never seem to fill with gas and can look mostly empty even when there's no problem.

Have you taken a look at the water separator? Ever drained that? Link below

Honda Outboard 75HP OEM Parts Diagram for Water Separator | Boats.net

Buy OEM Parts for Honda Outboard 75HP Water Separator Diagram
www.boats.net www.boats.net

I know those can cause problems.
Click to expand...
Not the lawn mower type filter but a see through marine type filter. I looked at the water separator closely and did not see any water in it but did not remove it yet.
I just can't understand why it's so intermittent. And why it restarts after priming and then runs fine for a while.
 
William01 said:
You mentioned new fuel lines, have you checked all of the shop’s work? All it takes is a distraction of the tech. working on your engine to miss tightening up something. Vibrations and nearly tight will find a way to make life difficult.
Click to expand...
I have double checked it but have not found anything yet. I see there are two crimped clamps on the fitting that goes from the gas line from the tank to the motor. So I am a little suspicious of those and will replace them with one hose clamp.
 
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