Weekend from hell...Need a fuel pump

[jleger98]

ok, so new pump and water/fuel separator are in. Just got back from the lake and it started right up and had no problems.

I got her all warmed up, then shut it down and let it sit for 15-20 minutes. Started it back up, and it hesitates a little when you jam the throttle from idle fwd to full. The more time you do it, the better it gets until after about 4 times the hesitation is gone. The hesitation seems to be at about 2000 rpms, but it will power right through it. If you accellerate more slowly to full, it doesn't do it.

Anyone have any ideas? Siphon valve?? Something else???

I've checked the siphone valve 2x and it moves freely.

[dogbert]

Check your distributor cap.

[TeamAllen]

I don't know? My fuel pump and cooler are coming Wednesday and we're leaving for Lake Havasu on Thursday.

I was hoping that would be the end of it. I will try and round up a new anti-siphon valve this week locally.

[dogbert]

My neighbor's boat would hesitate like that and then finally it wouldn't start. He had the distributor cap/rotor replaced and the thing runs like a top.

[teachercop]

Being I am experience similiar problems,,I have suspicions of the pressure regulator. The heat of the engine/fuel may be tweaking the regulator. I am starting with the fuel pump replacement, if that does not fully get it, I will look closely at the fuel regulator.

Spending the week at Havasu, doesn't get much hotter than there. We shall see.....

[Moki]

Hmmm, I wonder if running the blower would help then? I almost never use mine, but I really don't have any vents going into the engine compartment on my boat. It gets in through various gaps in the sides of the boat. I'll try and see if running the blower for a while fixes this. The problem is that the thing is soooo darn loud.

You can replace your blower very easily with a new quieter blower. Blowers get much louder as they get older.

[dogbert]

Yeah, they just replaced mine when I had mine in for a 100 hr service. Apparently wakesurfing is hard on my blower. I have this huge vent in the back and water just pours in whenever we stop. I may have to put in some type of flapper mechanism to prevent that from happening.

BTW, for those of you who have Mercruiser Tournament Mag engines, you need to replace your distributor cap/rotor every 2 years because they wear out. So, if your boat is running like it needs a tune-up, it's probably that.

[jleger98]

Dist cap, Interesting.....Can you get the same thing at an auto parts store or are they different? I'm assuming you need the rotor as well.

[dogbert]

Probably not, it has 4 screws to keep it on. Most automobile caps are clip-on.

They're pretty cheap.

http://www.iboats.com/mall/partfinde...n_id=547051540

[anhaney]

Dist cap, Interesting.....Can you get the same thing at an auto parts store or are they different? I'm assuming you need the rotor as well.

Go to CARQUEST Auto Parts they have a complete marine line where you can get a DIST CAP and rotor. Marine caps are diffrent they are not vented. The are sealed caps.

[dogbert]

Good to know. We have an O'Reilly near our lakehouse and they have some marine stuff...I'll have to ask them.

[anhaney]

Good to know. We have an O'Reilly near our lakehouse and they have some marine stuff...I'll have to ask them.

What you are looking for is any auto parts store that sells STANDARD Motor Products as there ignition line. Let me know the part number once you find the correct replacement. I may be able to hook all you guys up.

[jleger98]

Ok, got the new distrib cap/rotor on, new fuel pump, new water/fuel separator installed and tested the boat on a local lake and it seemed fine. (BTW, good tip on the distributor cap, it was past due) Drove the boat up to the Crosby mines. Spent all night Friday, and 3-4 hours saturday with no problems. Then the same thing happened again. Go to take off and it runs fine for about two seconds, then starts to die. at first, you can overcome it by pushing to WOT, but it gradually gets worse to the point where it wont run. Seems like the only fix is to take off the air cleaner and let it "air out" Almost seems like its getting too much gas. After it "airs out" for a while, it will start up and then you can sort of work through it by pumping the throttle etc. Eventually it gets better and we were able to save the day Saturday. Only took about an hour out of the day. same thing happened again Sunday.

Could this be a fuel regulator issue? I checked the siphon valve.....again, and the in-tank pickup, both are fine. If its not the anti-siphon valve, and its not the regulator, what else could it be???? Very frustrating.

[chpthril]

J,

Is your engine carb'ed or F/Injected?

[R&T Babich]

Is it very hot out when this is happening? Is it running fine when the temps are lower? It sounds like too much fuel when the temps are high. Check a spark plug when it's running good and again when it's not. Is your engine "throttle body injected"? Our 2000 350 Mag MPI is distributed injection. Our sends a vacuum signal to the fuel pressure regulator which I think causes it to bleed off fuel when the RPMs are low and allows max pressure at higher RPMs. One reference I read stated it is connected to "manifold vacuum" which is high at idle and low at WOT. I need to test it find out for sure. A leaking hose may give you max pressure all the time. "Wet" plugs will tell you if there's too much fuel.