225OX66 Question

[ahill]

This weekend I started my engines and both ran fine.
Shutdown & restarted the next day and found the port engine idled down & shut off.
Restarted and bumped up the rpms to 900 & no problem.
Took the boat out for a run & noticed my fuel burn was over 40 gph when normally its about 22 gph at 3600.
Starboard read normal port was greatly higher.
Are the two issues related and what is the solution?

 

[seasick]

This weekend I started my engines and both ran fine.
Shutdown & restarted the next day and found the port engine idled down & shut off.
Restarted and bumped up the rpms to 900 & no problem.
Took the boat out for a run & noticed my fuel burn was over 40 gph when normally its about 22 gph at 3600.
Starboard read normal port was greatly higher.
Are the two issues related and what is the solution?

First place to check is a leaking low pressure pump. I think you have three of them, Two are easy to get to but the third may be tough. Before taking them off, try tightening the screws that hold the covers to the pump body. Pump the primer bulb and look for leaks. The pumps can leak in two different modes; out the seam of the pump housing and out the back of the housing. When the back leaks, you may not see it but fuel will run into the exhaust housing. To look for the backside leak, you have to unbolt the pump from the block, pump the primer and see if fuel is leaking. Also note that the primer should get hard that could also indicate a leak.Low pressure fuel pumps only last a few years and all should be replaced at the same time. I am not a fan of rebuild kits for the pumps.
Next possible cause could be bad O2 sensor but that usually won't cause the motor to stall at idle. Finally, you could have a bad fuel injector that isn't closing or is sticking. Blacker smoke than usual could be a sign.

 

[family affair]

Seasick is right on.
To be clear, the primer ball will not become firm if one of the lp pumps has a ruptured diaphragm causing a leak into the crankcase.
If you find a leaking pump, be sure to check the O2 sensor. The rich running condition could cause the sensor to foul compounding the issue. Cleaning and/or replacement could be needed.

 

[Parthery]

Sounds like LP fuel pumps...they are not expensive ($40 or so apiece) to replace.

 

[ahill]

Thanks
No black smoke.
I have electric primers.
What about the gph discrepancy?
Boat runs great above 900 rpm's

 

[seasick]

Thanks
No black smoke.
I have electric primers.
What about the gph discrepancy?
Boat runs great above 900 rpm's

What year?
225SXs have three low pressure pumps and i don't see electric primers in the pars diagrams that I have.
With respect to fuel burn, if the pump diaphragms are ruptured, you pour raw fuel into the exhaust thus the higher burn numbers. The pump output depends on revs to an extent. If one or more are bad the gas flow at low revs may be below what the motor needs.

 

[ahill]

Thanks everyone.
Seasick,the priming pump is not a part of the motor.
It replaces the priming bulbs.
Probably a ruptured diaphragm causing both issues.

 

[seasick]

Thanks everyone.
Seasick,the priming pump is not a part of the motor.
It replaces the priming bulbs.
Probably a ruptured diaphragm causing both issues.

Interesting. On my 150SX, I never and I mean never pump the primer before starting and the motor starts every time within 5 seconds. The only time I use the primer is the start of the season when I manually pump to refill the motor mounted filter and VST tank which I had drained as part of my storage routine.

 

[ahill]

I only hit the primer if the boat hasn't been run in a while.
FL lobster season thru January it gets little use other than a waterfront condo as I lobster on my 17 Mako. Then all sorts of birthdays, vacations and holidays kick in to limit my use. Kind of like winterizing during that time.

 

[seasick]

I only hit the primer if the boat hasn't been run in a while.
FL lobster season thru January it gets little use other than a waterfront condo as I lobster on my 17 Mako. Then all sorts of birthdays, vacations and holidays kick in to limit my use. Kind of like winterizing during that time.

Unfortunately for various reasons, my boat sat for many weeks at a time this past season but I never had a problem starting. One advantage to not using the primer is that you will get some warning when the low pressure pumps are going bad since the motor can be harder to start or stalls after starting. I am not sure why but the problem seems to be more of an issue in colder weather
(perhaps the mixture just can't get rich enough for the air temp)I have had those LP pumps go bad but not leak at all. Although the diaphragms were not leaky, the internal check valves were not up to par and that results in low gas flow.
As you have also pointed out, you didn't see black smoke, a sign of too rich a mixture. I may have provided misleading info on LP pumps and black smoke. Since the raw fuel that may be leaking into the crankcase does not usually get burned, the exhaust won't look black. You may or may not see a gas sheen on the water.