2001 0x66 250 Bog & Cut Out Issues

[bonafishark]

I have been trying to resolve my issue and really need someone to point me in the right direction.

Background: 2001 V250 Saltwater Series engine has approx. 400 hours on it. Used every season from 2003 except last season-regular maintenance performed yearly. Boat sat out last season. Never had issue before using this season.

Symptoms: Engine will start up and idle fine. Sometimes, maybe 5 minutes into or 30 minutes into, when opening up the throttle, she will bog out and die. Have to wait a good 20-30 minutes before she will start again. Sometimes she will be fine cruising around 4000 RPMs, than shut off the engine to fish for an hour and after maybe 2-3 minutes of starting and throttling up again she will bog out and die. Sometimes she will run fine after sitting for the hour. Sometimes when hitting someone's wake or a wave she gives the impression she wants to bog and sometimes if I throttle up she will resume and sometimes she will cut off and die. Always take 20-30mins before she will run again. Usually I have to tilt the engine up to restart. Have not been able to start in the water with the engine down. Today I noticed some slight surging. I also noticed that the RPMs seemed a couple hundred off from where the throttle handle was positioned. Problem seems to be getting worse and becoming more consistent. (The 'sometimes' above becoming 'always')

Diagnostics: Have filled up tank 3 times so far-doubtful it is the gas. Checked anti-siphon valve-working fine. Replaced fuel/water separator. Checked all fuel lines from tank to engine. Tried running with auxiliary tank. Replaced priming bulb. Replaced the engine mounted fuel filter. Plugs are clean. Checked the anti-siphon valve located between engine mounted fuel filter and 1st fuel pump.

Things I noticed so far: Priming bulb will get pretty hard but not rock hard. For the most part I do see fuel being dumped into the engine mounted fuel filter-remains at ¾ full. Bulb does not collapse after the engine cuts out but is not exactly firm either.

Any help is greatly appreciated before I have to hand it over to the mechanic and get blasted with mark-ups and a huge labor bill-even if for only an hour of work.

Thanks in advance.

[Salty Dog]

I would check the low pressure fuel pumps.

[jb123]

have you drained and or cleaned vst tank and filter?

next time engine cuts out and wont start, check for spark. because it is so intermittent sounds like an electrical issue to me.

[bonafishark]

I havent drained or cleaned the VST tank because frankly I am not sure where it is located. I have tried to research online but have come up empty. I have ordered the service manual. Could you possibly clue me in while waiting for the manual?

Will also check for spark. Unfortunately she does fine at the dock so I have to risk getting stuck.

[bonafishark]

Manual came today. will start with the VST tank and filter.

[jb123]

if it is vst filter or not it should be done and done regularly.

also you can try unplugging the main 10 pin harness while running, to isolate issue from front end components and motor. for ex. if it was a switch with harness unplugged the issue wouldnt occur.

[bonafishark]

Thanks. VST filter had decent amount of debris. Suction was much better after I cleaned it. I also noticed some of the diaphrams in the fuel pumps were starting to corrode. Going to mount a kicker before I test it out as I had to get towed in last night. Than will try unplugging the wire harness.
Your input is appreciated!

[bonafishark]

hey jb123, thanks for your continued input. Anything else I can look into while I'm in there?

[bonafishark]

Cleaned the VST filter, put back together with new gasket, turned the key, heard the HP pump come on for the 5-8 seconds and she started right up. I let her idle for 20 mins, shut off, and tried unsucessfully to restart. Did not hear the HP come on this time.
My question is: Do you think it is possible to have a bad HP pump that only works intermittently? If a HP pump was bad, would it work at all or only sometimes.
I checked the pressure in the VST lines along with the fuel pumps and they were all in line.
I also checked all of the electrical connections to make sure I did not have any loose or corroded wires and everything was intact.
I did notice in the manual a way to check the electrical connections which I will do.
Any input is appreciated before I spend the 700 or so for the new pump.

Thanks

[jb123]

again you need to check for spark when this occurs....could even be as simple as a kill switch on its way out.

[bonafishark]

Thanks. Will do today.

I have the same engines and had the same exact issues you are having and it was the low pressure fuel pumps. I replaced all three and the problem was solved. Make sure there isn't a pin hole, gasket off a little etc. as this will cause a drop in the fuel flow to the high pressure tank and as you are throttling up the demand on the high pressure tank will exceed the supply and the engine will bog and stall. Good luck

[bonafishark]

Update: I have narrowed it down to the Hp fuel pump in the VST. This pump is working intermittently. It will just shut off and the engine obviously dies.
Turning the key, if I hear the pump kick on-engine starts fine. Turn the key, dont hear the pump, engine will not start.
I am guessing it is either the resistor or a relay switch.
Would these cause this pump to act like it has been acting?
I checked all of the connections for loose wires, grounds, ect., but have not found any.
I checked for spark when the engine would not start and have it.

Am I on the right track?

[bonafishark]

ok, narrowed it down to the main relay. voltage going is was 12 volts and when coming out, the HP pump was on and all worked ok. When not getting voltage out, HP pump off, boat wont turn over.
when all working ok, can hear the distinct clicking of the relay. when not, no clicking.
I always have spark and voltage into the relay.
so I assume the relay is faulty and needs to be replaced.
just wondering if there was anything else to check out before spending the 160.00 for the part.
Is it possible there is a loose wire in the relay and could be repaired? I dont think so but worth asking.
Thanks for the help, it is much appreciated!