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Surfer
11-26-2003, 08:19 AM
Ran my 18 off shore yesterday, little rollers, lots of air, ran WOT about 40 miles like a bat outta...ran a few miles at idle, then when brought back up to speed, it acts like its starved for fuel, has hesitation, bogs out. This happens every time I run it, great for the first two hours, then...What could it be?

olredalert
11-26-2003, 08:59 AM
------Out bouncing around,Huh! Sounds like you shook up some crap in the tank and plugged up some part of the fuel system.What kind of fuel filter are you running? Can you check that out?...........Bill S

boldts
11-26-2003, 09:03 AM
Surfer, been a while, but let me take a shot at this one. The members will chime in if I'm way off base.

I suspect possibly one of 3 things.

1. Vapor Lock - This is caused due to the heat of the engine vaporising the fuel before it can get to the combustion chamber. Usually it is caused by a rubber fuel line laying on the intake or near a heat source like the exhaust manifold.

2. You mention it runs like it is staving for fuel. I believe it will also run like this if the carb is flooding. To much fuel caused usually by a stuck carb float.

3. Bill beat me to it. Dirt in the fuel system. What year boat? Original fuel tank?

I may be wrong, but those are the 3 items I'd start with. Do you have access to a different carb to put on the engine and run? If so, it's a fairly simple change. You could also either do it yourself or have someone check your carb float levels and or rebuild it. As for the vapor locking I'd follow your fuel line coming out of the fuel pump to the carb. If it is rubber hose, I'd probably change it to a metal material and be sure that when you form the tube up to the carb to leave 1/8 to a 1/4 inch of space off the engine. I'm not sure if steel tubing is used in marine applications. If there is trash in the fuel system, it may lead to a winter project for you. You can try first having all the fuel removed. Take a look and see if there are particles floating in the fuel. If so, fuel tank may need replaced. If not, maybe like Bill suggested, you just need to replace the filter.

One other thing you didn't mention. Even though it hesitates, once the boat gets going again, does it smooth out and run normal or does it bog and hesitate all through the RPM range?

terry
11-26-2003, 09:10 AM
Olred, is right on the money (as usual :) )
Check the fuel water seperator or fuel filter first.

ToonaFish
11-26-2003, 09:18 AM
I'm thinking it needs to be winterized...

Bunches,

Celene 'cruel, boating in November is cruel'

mattyboy
11-26-2003, 09:34 AM
It's fine for the first 2 hours???
well then only take 2 hour rides wink :D
sorry couldn't help myself

I had similar problems that I thought was a carb issue wound up being the cap and rotor,
but I think the fuel filters are a good place to start.

is it hard to start??

Matty

Surfer
11-26-2003, 09:39 AM
Toona, and it was a beeeeutiful day, flyin' fish a flyin' the whole deal.

boldts, 1) brand new (about a year old) quadra, fuel line from the pump metal, and offset to the block all the way. 2) bought new water seperator, last week, old one had a little crap in it but not much, boat is an 85 but is in great shape, can't see going through the agony of replacing the tank, isn't there a way to wash / flush it clean. It does not smooth out, actually gets worse as you advance trottle.

Surfer
11-26-2003, 09:44 AM
An after-thought, I do not have a fuel filter, could someone suggest a part, and I assume it be be inline, ahead of the pump. Thanks

Surfer
11-26-2003, 10:40 AM
It starts with the fisrt flick of the key, and runs great for that "2 hour ride". What could change in a couple hours time?

BUIZILLA
11-26-2003, 11:00 AM
My Minx does the same thing once in a while...same 2 hour span, comes and goes... haven't nailed the culprit yet myself.

J

turbo2256
11-26-2003, 11:09 AM
There is or was a guy around Stuart Fla that would or could clean out your tank and give you an exact figure on how many gallons it held too.

olredalert
11-26-2003, 12:08 PM
-----What type of carb? Does it have one of those brass fuel filters right as the line goes in the carb? You wont see it externally. You will have to take the fuel line off at the carb to see if you dont already know. If its there just remove it. If you have a source of air-pressure you could gently back flush the line from the water seperator back to the tank. You may get lucky and actually hear/feel a slight pop as the obstruction is forced back into the tank.
-----If any of this stuff works,you probably are in for a tank cleaning. The best kept boats accumulate debris in the tank,so dont feel like you have done it a great disservice. It happens!...........Bill S

1996Z15
11-26-2003, 01:05 PM
I have had the same problemm with my 86 Minx. I changed the water seperating fuel filter, the cap, rotor, wires, plugs, checked the brass screen in the inlet to the carb and sprayed carb cleaner all through my carb. I even added some of that water absorber to the fuel. It cleared up for a little while but came right back. What made the biggest difference, believe it or not, was when I took the boat out for the last time before winterizing it. Granted, the air was quite cool but I put in this big ass battery from my neighbors Chaparrel (mine had died) and the difference in performance was amazing. I don't know if it was the air, the battery or just a coincidence but the boat never ran better.
I doubt that this helped you at all but, thought I'd let you know that I did everything I could think of and the problem persisted until I changed the battery....or was it the cold air?

olredalert
11-26-2003, 03:01 PM
------Z15-----You may be having an alternator problem or possibly your battery was going bad.When you un-winterize check alternator output,as well as battery wellness............Bill S

Cuda
11-26-2003, 06:36 PM
I had the same problem once on my fish boat. I'd take it out about 15 miles and about 5 miles from making it back it would start missing real bad and run like crap, but wouldn't die. The problem drove me nuts. Finally, I pulled the fuel pickup and found a hairline crack about halfway down. Once the fuel got below this level, it would start sucking air.

mattyboy
11-26-2003, 07:04 PM
Originally posted by Potless:


Scary as it may sound to us all, Matty actually has a good point.. Jeesh that has never happen before eek! :rolleyes: :confused: :p wink :D

Matty

Walt. H.
11-26-2003, 07:44 PM
Cuda,

Thats a very Commom problem and that's the cause.
When the brass pick up tube has moisture on or in it during the winter and it freezes, bingo, it cracks! also vibration will do it to. :( eek! :(

You win the gold star

Happy turkey day to all,
Gobble Gobble!

Walt :)

Kong
11-27-2003, 08:01 AM
Here's another possible reason for bogging. Water in fuel tank and carb. Fine running at idle but either sputtering or bogging at increased throttle. Fuel/Water Separators couldn't keep all the water out of the carb. Mimics an ignition problem. Pop the carb (if you have one!) and dump upside down to drain. Drain tank completely w/ siphon or squeeze bulb the tank into an outboard tank to fully remove gas/water. Stuff rag into sending hole and mop up excess in tank. Pour a little alcohol into tank and add gas. We have had a number of boats come in this season with a LOT of water in the tanks and this was the only way we were able to get them running right. A lot of you out there, I'm sure, are well aware of these symptoms and solution. Just my 2 cents.

The Kong.

marcdups
11-27-2003, 01:47 PM
surfer, check your pick up in the distributor, we have had a lot of failures here when they get hot, just a thought, Towel boy

FARJR
11-28-2003, 09:48 AM
I just fixed that problem on my classic 18. I figured out that it was crap in the tank. I put an inline fuel filter in and along with some additives in the fuel. After two three runs and replacing the filter two three times the problem I ran the crap thru.

Frank

tailwind
11-28-2003, 07:40 PM
Oredelert: You may just have an asnswer here!

Many or several years past,My dad, and a very good friend, were able to have fun on an old 27 footer wooden hull sportfisher, out of Cape May, New Jersey. Having skipperd this vessel at the age of 13 alone, out past the 6 fathom light, we are well aware of your dilema!

this was an older Chrysler 318 marine engine, but as an older sailer, will try to be accurate as possible. After a couple of hours, the engine would indeed go south, leaving us to wonder? Nevertheless with the help of jiffy peanut butter, and perhaps other potted meat, the old faithful would fire up and get us all home!

Anyways, with only a chance, one night, we did figure everything out!After a compression check, we did indeed found the culprit! A very weak coil - which would only show up when needed! Ever since then no problemo!

Rootsy
12-01-2003, 01:53 PM
gawd, as frightening as this is... i am gonna have to go with TW on this one... check the coil, if she is getting hot on you and breaking down this could be your problem most definitely. It can drive you insane to find sometimes... the motor should just feel down on power.. btu once she cools off and sits a bit things are back to normal til you run ehr hard and it breaks down on you again... the coil is relatively easy and inexpensive to replace...

a fuel starvation problem will feel much different... instead of just down on power, fuel starvation will give you a NOTICABLE drop-off in performance the more throttle you apply... you['ll reach a point where it peaks.. then gets lean the more you open her up... you may even get a backfire through the carb if lean enough on the low end... fuel filters don't generally mysteriously unclog themsleves until the next time either... so this scenario has me skeptical of a fuel issue...

i had a disheartening episode last fall after doing some motor work and not reaping much benefit... before visiting friends i came to find a dead battery so i swapped batteries since i had a spare in the shed.. and whala... i picked up 500 rpm... that's like 50 hp in the lil 16... come to find out i had a 1 year old battery with a bad cell and when left to sit would discharge on it's own...

Surfer
12-01-2003, 02:56 PM
The mystery continues....went skiing Saturday, problem was there, but intermiten (need spell check) ran tank all the way down, and checked filter at carb inlet and was clean, no crap in seperator either. I have a dual battery setup, that I alternate, and problem appears on both batteries. Looks like a coil replacement...Stay tuned!

BigGrizzly
12-01-2003, 06:22 PM
If you have an early Donzi there ia a screen on the botton of the furl pickup tube in the tank that gets clogged.when you stop and pull the inline filter the vaccume is released and ythe crap falls off ans runs fine for awhile. On my Corsican i took off the screen and put a good filter in the line, the filter was big enough to take it all and keep going. About 3 weeks later I took the filter off and tapped it and all kinda of crap fell out.