98 S/N loading up GT-40

[walleye]

When the weather get's hot and my boat sets for while, it loads up  when you fire it up. Once it sputter's abit then it runs great, no evidence of performance loss. I have a buddy who has a 99 that does the same thing. Sorry i would post this Planet Nautique but I forgot my pass word and the dag-gum thing knows my e-mail and I cannot get in. I change my Hi pressure pump filter, cleaned spark arrestor, plugs, wires, rotor and cap. It has done it for about 5 years now. Jody/AB or anyone out there have any suggestions.

[A_B]

 

Nice stringer in the pic.  Reminds me of the last time I went fishing with my dad.  The first fish of the day was my 32" that broke our net, landed it by wrapping a rag around his hand.  Next in was a 29".  What a day.  Never caught two like that before and ever since.  Great memory.

 Regarding the boat, have you changed the fuel cannister filter?  Everyone seems to forget about that, I know I did!

I believe the low pressure pump really controls starting and low idle, it is housed in the fuel cannister.  I believe there is a pressure check on the fuel cannister that you can hook into, if you have one.  I bought a new filter, pump, and then relay, with the relay being the problem.  Mine just wouldn't start, then start and run fine.  You sound like it is more of a fuel supply.  

The relays on the back of the engine are usually noticed failing by not starting at all, or a quick fire and die, almost like a kill switch, on off.

[RichardDoane]

low pressure pump should be tested to make sure it's ok, and the pressure gauge will tell you the answer. it should be supplying low pressure/high volume to the cannister pump. the cannister pump should be giving system pressure for the injectors. with the gauge atached to the fuel rail, notice the resting pressure, and how long it takes to bleed off, if it doesn't prime right up to specs than there's your sputter. either the injectors are bleeding off, or the fuel pump check valve isn't holding pressure. not sure what the pressure specs are, but the the techline, or planet nautique, or a CC dealer will know.

[A_B]

Richard got me thinking about it, and I said the low pressure pump is in the cannister, which is incorrect.  It is located outside the cannister, and feeds the cannister with fuel, which had the main efi pumps sort of dangling from the top, which in turn feed the fuel rail.  It is a fairly small unit, mounted close to the cannister.  I have the old low pressure pump somewhere in my garage, that I think is good, as my trouble ended up being the relay.  Email me if you have an interst in getting it cheap.  amjbishop at yahoo dot com. 

My thought on my boat was to just replace the low pressure pump from Skidim, as it wasn't that expensive, and by the time you go to a dealer with a gauge and all, I figured I just had a new pump for my old boat.  I also bought a filter in the cannister, after like 7 years.  The guys I ski with hadn't done it either, so I didn't feel that bad. 

See the PCM GT40 engine manual at link below, about 300 pages in PDF format on PCM or SN website. It has all the specs and troubleshooting guide. It was very good info.  

http://www.planetnautique.com/CorrectCraftManuals/GT-40%20Service%20Manual.pdf

One other thing you can do is clean out the checkball valve sitting on top of the fuel tank. Mine was marked with red tape or something as there are a few, mainly for venting and return from the pump. If this is sticking, due to Stabil or whatever, fuel flow might be compromised initially. This is a long shot, but cheap one. 

Low Pressure Fuel Pump:

http://i109.photobucket.com/albums/n73/ab38off/fuelpump.jpg

 

 

[6balls]

My buddies GT-40 starts up fine, runs strong, but then starts coughing/backfiring/dies mid-set and won't start again.  Seems less frequent w/tank more full.  Hours later will start and run again.  Had some gunk on the intake screen in the tank, cleaned it out but didn't help.  He's stubborn about taking it anywhere to get looked at by s'one who knows what's up.  I'm thinking fuel pump fails after running for a bit.

Thoughts appreciated.  Tired of paddling home. 

[A_B]

6B, my problems started like that, then eventually, would just die completely, and not start.

Ended up being the relay switch on the back of the motor.  I guess it is very common for them to fail after several years.

Hard to tell exactly, but I would make a WAG that he is headed for what I had.

Skidim had them.  USAWSA gets 10% discount.

[walleye]

Thanks fellas

AB dropped ya a note

[A_B]

 

6Ball, when I was trading emails with Walleye, I remembered the key to diagnosing the relay problem.

When in your garage, turn the key on without engaging the starter, and you will hear the low pressure pump priming.  It pulls gas out of the tank to prime the high pressure pumps.  It does this everytime, whether it is primed or not.  So, if the boat won't start after stalling out on the lake, open the motor box and do the same, listening for the priming.  If the relay is bad, you won't hear it prime, there is no electricity getting to the pump.  This will save you $120 on a low pressure pump if the relay is bad.  The relay is a lot cheaper too.

 

[6balls]

Given it's winter, tougher to remember, but I believe when the key is turned in his boat, even when it's dead mid set post sputter and die, the pumps still squirt when the key is turned. 

 If that is the case...low pressure pump problem?

[A_B]

If you know anyone with a fuel pump pressure gauge, check

It first. I would also check the cannister filter. They say

To change every year but the guys I ski with didn't even know

About it, including me.

 

The pump is about $120 and less than 30 minutes to change.