5.7 missing and dying - Maxum Boat Owners Club

No1hedberg · 06-05-2011, 06:28 AM

Hi everyone. I love this forum since I found it, and I wondered if I could pick your brains. I have a 2001 2100 SR with 5.7 2bbl carb, and about 80 hours on it. I'm having an apparent fuel problem. When I put my boat in and run it, it runs great for awhile. Later it starts missing, and will stall. Putting it back to idle, will keep it running sometimes, but it usually won't move much above idle without shutting off. I started trying to diagnose the problem while on the water, and found that If I take off the fuel filter (water separator/fuel filter spin on type) and empty it out and put it back on, the boat would start and run strong for about a mile or so, then again missing and shutting down. My conclusion was bad fuel from sitting. I pumped out the entire tank with a see through filter where I could watch it come out, with very little gunk in the filter. I put on a new fuel filter and 20 fresh gallons of 89 octane, with dry gas treatment, and went back to the lake today. I ran up and down the lake cruising 25- 30 and at speeds over 50. Hit wakes, tight turns, anything I could think to replicate the problems. Thought I'd fixed it. Started pulling my son on the tube, and problem resurfaced. It seems as though if you sit for awhile after stalling, it will run normally again for awhile. I'm wondering now if emptying the fuel filter was doing anything, and it was only working again because it sat for awhile, while I took the filter off and on. I put new plugs in last summer. I wonder if tight turns pulling the tube is doing something, but it seems to miss and stall while cruising in a straight line. I'm kinda stumped. Sorry for the rambling post. If anybody has any advice I would definitely be appreciative. Thanks.

CountryME · 06-05-2011, 12:37 PM

Hedberg, have you checked the fuel tank vent? It seems to be acting like you have a partially clogged vent what will allow a little air into the tank as it gets drawn down slowly, but when you romp on it the vent can't keep up with the vacuum that is being created in the tank as the fuel is drawn down quickly. Good luck.

-JP

seapuppy · 06-05-2011, 02:18 PM

this sounds logical...but let elliminate another option...since it runs fine for awhile, then stalls and dies....if it's not water...then the only thing it can be is electrical or vacuum....so....since the electrical issue isn't happening..ie engine is still running and starts ok...then that leaves vaccum.....so...run it like you stole it....when it starts to act up....open the gas tank filler cap....see if that doesn't solve it....that would indicate the vent as jp stated........
clear the line with a wire or replace the vent hose....make sure it's run with no kinks at all....

sp

No1hedberg · 06-05-2011, 03:24 PM

You guys are the best. Sounds logical. I am gonna try to get back out today. I'll give it a try. Thanks.

No1hedberg · 06-06-2011, 03:07 AM

Update: I took off the fuel tank vent hose at the tank and blew compressed air back through it. I also took off the carb, and sprayed it out like crazy with carb cleaner. I ran the boat all afternoon and had no problems. Right before we packed it in for the day I took my son tubing again. After tubing for about 30 minutes at the end of the day the boat quit again. I took off the fuel filter and didn't see anything in it, nor did I empty it, but it was only about 1/2 full. Every other time I took it off the fuel was running over the top. I put it back on, and the boat ran fine back to the boat launch...About 2 miles. I guess I'll have to keep at it.

To add insult to injury, the boat didn't go straight on the trailer and got stuck when I was backing up to get it straight. It popped loose from the trailer, and smashed the sun deck into a pole. it cracked the fiberglass. I wonder how serious this is, and how much it's gonna cost me?

seapuppy · 06-06-2011, 03:25 AM

ouch....first off...next time you run it and it dies...remove the fuel cap only...not the filter.....but the filler cap.....then try starting it.....it might be the pickup tube in the tank.....

2nd off...your looking at about 500 bucks to repair the fiberglass....your going to definitely want to find a good fiberglass guy...they can do the repair and you will never know it was damaged.....

keep us informed...

SP

rens914 · 06-06-2011, 12:00 PM

this sounds like the problems i had with my boat
ended up to be water in my tank
rens

No1hedberg · 06-06-2011, 03:19 PM

Quote:

Originally Posted by seapuppy

ouch....first off...next time you run it and it dies...remove the fuel cap only...not the filter.....but the filler cap.....then try starting it.....it might be the pickup tube
SP

I did take the cap off while I messed with the filter to let the tank vent. I didn't want to run the boat with the cap off because it's so close to the water line i didnt want spray getting in there. I did put the cap back on very loosely about a quarter of a turn.

seapuppy · 06-06-2011, 03:25 PM

then it has to be the strainer on the fuel tank......

see if you can borrow a marine type fuel tank...like for an outboard engine....disconnect the fuel line and plug it so it doesn't leak gas from the fuel pump...
connect the portable tank to the fuel pump...run it like you normally do...if it doesn't start to lock....there's your problem...the fuel line is either bad or the fuel pickup in the tank is blocked or partially blocked...or the vent tube to the side of the boat is blocking or kinked someplace....

oh....check to see how the fuel line is run in the engine bay....if it gets too hot...it might be vapor locking...not likely if it's run along the hull stringer as most are to help keep it cool and away from the engine...

SP