Engine mis-firing?

[TroutCowboy]

OK, all you WL junkies, you haven't let me down yet, let me throw something new at you...

I have a '94 Glastron with a 5.8 liter Volvo Penta and a bad case of the hiccups. If I feather up the throttle I can get her up to speed without issue, but if I dump it to get up fast, it coughs and spits and cuts out. I thought I might have picked up some bad gas (water or something) but I just topped her off with 7/8ths of a fresh tank and still have the hiccups.

I don't know anything about fuel-injected motors, but my best guesses are:

a) I need a new fuel filter. Maybe when I'm really demanding a lot of gas go through it, it just can't keep up.

b) Fuel injectors clogged (or whatever). Fuel is not being adequately sprayed into the cylinders.

c) Other (plugs, ignition, ???)

I am going to try the fuel filter first -- it's cheap enough and easy enough -- but am open to any and all suggestions. Anybody go through a similar issue and have an quick & inexpensive (purty pleez) solution?

Thanks!!!

Johnny

[Easy Limits]

I would start with the easy and cheap stuff first (filters, plugs, wires) before you start tearing in to the expensive stuff (fuel injectors).

[zen leecher aka Bill W]

clean your plugs first. Every time mine starts acting up it's dirty plugs.

[hewesfisher]

If it's been awhile since the fuel filter has been changed, that's the first thing I'd do. I've had similar problems with fuel injected cars, weak acceleration, no power, stumbling, etc., and on two separate cars it was the fuel filter. If you're behind on regular maintenance (plugs, etc.) then I'd do them after I changed the fuel filter and verified whether it ran better. You get to changing a lot of things, and then you won't know what made it better, or sometimes, worse. Good luck!

[Marc Martyn]

If you can add injector cleaner to the gas, you might want to try that. I do that with my F150, 4.9L, about every 3,000-5,000 miles. I do a lot of in-town driving and it has a tendency to load up. When I am going on the interstate for a couple of hours, I put a bottle of that in when I fill up. It helps greatly with the idling and acceleration.

[jmay]

Volvo makes a good outdrive, but the engine is a 5.8 Ford 351 correct? Do you have a fuel/water seperator? Being a runabout you may not, but if you do, look there first

Along with everyone else advised I would change the plugs, and fuel filter, as well as put in some fuel injector cleaner first. Total bill will end up being $40 and a hour of work and should work. I worked at a marina for several years, and have been a boat insurance adjuster for 10 years, with your symtoms 9 times out of 10 its bad gas. At $3.00 a gallon its gainful but after putting in the new filter and injector cleaner run it on a plane for an hour.

[mallard83]

I am fairly good with fuel injected motors and all of the things mentioned above are a good place to start. There is at least one thing that has not been mentioned yet, and that is the air filter. A lot of times when an air filter on a fuel injected motor gets to dirty or wet it will not get enough air. This sends false signals to the computer which in turn the computer sends the motor the wrong amount of fuel. The motor will run rough especially if you punch it really hard because it is trying to hard at that moment to take in the amount of air needed. Also the timing may need adjusting, so you could check that. Good luck.

[jmay]

GREAT CALL MALLARD!! Cowboy I think Mallard could have found the problem. Your boat ran good all summer and than not so good on Labor day weekend? We had a big thunderstorm friday 8/31/07 the wet air filter could be it

[jmay]

Ethanol's Gas (E 10) can hae adverse effects to boat motors involves all types of performance issues and disintegration and deterioration, drying and clogging of engine parts.


Signs and symptoms of ethanol problems and damage include:


Stalling, prematurely worn engine parts, rusting, clogging of fuel filters and carburetor jets, release of gunk and sludge throughout the engine, frequent water-contamination/phase separation of fuel, and eventually engine breakdowns and death.


Ethanol can cause a motor to run lean on fuel, due to water will not burn, which will take the place of fuel.
Vapor lock (fuel starvation) is common when using ethanol fuels.


Alcohol fuels are very prone to phase separation, when the weight of the ethanol and water will sink to the bottom of the fuel tank and get picked up by the motors fuel system. (Even small amounts of water can harm the fuel system).


The initial symptoms, (of using a higher than acceptable concentration of alcohol in fuel, is usually engine stalling when you demand acceleration (WOT).


You'll notice other performance issues, such as increased stalling, misfire, hesitation and difficulty maintaining boat speed during trolling.


The long term dangers of ethanol (and other alcohol-blended fuels) are many, including deterioration of parts (rubber, aluminum, fiberglass etc.), rusting, fuel system clogging, and other varied damage to engine parts and components. Older engines are more prone to ethanol alcohol damage.


The most reported and troublesome issue with marine engines and ethanol fuel has been regarding the decomposition of certain fiberglass gas tanks. There really is no solution to this issue, other than to replace the tank (very costly, time-consuming project); Lining or sealing the tank, for added protection, is sometimes possible.

[Marc Martyn]

Wow! Great stuff. Where can I get some!

[TroutCowboy]

great advice, guys! i spent today replacing everything i could do myself to save the $60/hour head-scratching fee at the dealership. the guys at two different shops had two different ideas -- fuel filter and/or fuel pump.

as it turns out, volvos (and maybe others) have two fuel pumps. The "lower" unit pumps the gas out of the tank and the "upper" pushes the gas into the cylinders as directed by the fuel injection computer. They suspected the upper one might be failing because of how the coughing happened at higher RPMs.

additionally, i found there to be two fuel filters -- an inline one and a filter/water separator hanging under the fuel pump. when i poured the contents of the old separator/filter out there was no obvious culprit lurking within. it looked a little light in color but after an hour or more of sitting i didn't see any separation.

anyway, for less than $20 i was able to replace both myself. i hooked up the fake lake and it fired up first try (great thing about electro-mechanical fuel pumps -- as soon as i turned the key forward i could hear it whizzing and pumping gas thru the empty lines). i pushed the transmission-disengage-button-thingamajigger and was able to rev up the engine a bit w/out hearing the coughing/sputtering. that was as far as i wanted to try things with the outdrive not sitting in water. i'm taking it out to a close-by lake tomorrow for a trial run. i'm anxious to see if i get teh same good results when the engine is under a load.

if i still have the problems i'll try some of your suggestions like the fuel injector cleaner, fuel dryer, etc. i have to ask about the air filter -- to my knowledge there isn't one??? i have a spark arrestor only, unless there's some paper filter or something under/inside it? i'll sure look for one, cant' be a very expensive item.

my best guess is still bad gas. even though i put in 7/8ths of a tank worth of fresh gas in, the damage may have already been done to the fuel filter/separator. a guy can hope, right? sure would be nice to have fixed the problem in an afternoon for only $20!!

thanks again for all the advice & info guys! i'll let you know how it goes tomorrow.

[mallard83]

if i still have the problems i'll try some of your suggestions like the fuel injector cleaner, fuel dryer, etc. i have to ask about the air filter -- to my knowledge there isn't one??? i have a spark arrestor only, unless there's some paper filter or something under/inside it? i'll sure look for one, cant' be a very expensive.

The spark arrestor should be in with the exhaust, not the intake system. I was not even aware that boats had spark arrestors. Your motor most deffinatly will and should have an air filter because any motor needs some sort of air filter in order to keep contaminants from entering the engine and damaging sensitive internal parts, especially water with a boat.