engine question

just bought a used boat and there is no power or punch when in gear. revs up fine, but has been stored for a few months. things i'm going to do:
check spark plugs
compression
i believe it's a carburation problem
when i ran it yesterday it would sputter. it's got a 5.7L/V8 and took 22-23 seconds to plain out(about lil over 100 yards) and only hit 34mph maybe 3 times in 35-40min. of running the lines out. new to the direct drive/comp ski boat arena. looking for any advice beside just get my money back. haha. at least my 16ft tri-hull with a 85 johnson outboard ran consistently and faster--and it's 30 yrs old!!

You are probably correct with the carb. I would take it apart and clean it. Possibly the secondaries aren't kicking in. Similar thing happened to my friends sportster a few years back. Cleaned the carb and it was good to go. I would also check the points and timing assuming it doesnt have electronic ignition.

1. Clean the carb.
2. Change the fuel filter.
3. Verify pressure on the fuel pump.
4. Clean out the gas tank.

The last on was the source of my trouble. The gas tank intake would clog up due to rust and debris. The other items failed due to the gas tank.

What kind of boat is this? How old is it? How many hours on the engine? Any story behind it?

When you say it was stored a few months, does that mean it was used during the winter?

If the "sputter" is a hesitation when you accelerate then it would indicate that the acceleration pump(s) are not working, which in turn could indicate that the fuel delivery to the carburator isn't working.

If the fuel pump is Okay then I would guess that the carburetor has been fouled, possibly with bad gas. If it has only been a few months then I would be surprised that the gas went bad. If it has been a few years, then you need to get rid of all the gas in the tank AND rebuild the carburetor.

A compression check and timing check would certainly be a good idea.

Might want to check the ignition set, too. Couple of years ago, I had a friend who rebuilt his carb twice, replaced the fuel filters, and completely emptied his tank, thinking his problem was fuel system related (engine shooting ducks under load). Wasted his whole summer on the fuel system, turned out to be bad spark plug wires. I'm not saying to ignore the possibility of a fuel problem, but if that doesn't pan out, spark plugs & wires are relativly inexpensive, and easy to DIY.

well, the original owener came by and we put new spark plugs in. no luck. prior to that i checked the compression. all equaled to 130. when looking down the carb i saw erosion on the intake. i think it's the carb.
the boat sat since october. but even though it was covered and tarped on top of that, we had one of the worst rainy winters.
i bought it on wed., took it out thurs. and this all happened. the seller has offer to pay half of a new carb, but he advertised it as "runs good, lake ready" so i expect him to pay full or simply void the sale. i don't want there to be more than just carb issues and this get messy. but i'm looking out for myself and what the boat was advertised as.

As socalwakepunk said check the ignition system especially the timing, for points and full advance.

How does it idle? What if you put it in neutral and slowly take it to 2500 RPM's? Is it still smooth? What year is the boat? Which carb? What if you inject propane down the carb? Was the boat stored with an empty fuel tank?

it is a '90 malibu skier. i has a quadrajet carb. the timing does advance. it seemed to labor when i set the idle below 800. so it's at a lil over 800 to about 900 rpm. when throttled the secondaries don't engage as til late. i just spoke to our race car mechanic and he said it's the carb and would be simple for him to rebuild it with a new kit.(about $50).
i did adjust the carb breathers and nothing. which apparently shows there is something plugged.
the boat was stored with some gas in the tank.
the previous owner is as shocked as i am. but he should have no problems paying the full amount of a kit. if not he'll end up paying for the kit and labor or he'll have some small claims issues with false advertisement.

oh, peter c, sick willy's!! my dream vehicle is a '67 commando!! a rare old jeep. one day my goal will be reached of having one restore from the ground up to my likings.

Quadrajets are great carbs. There is probably just a jet plugged or something. Sometimes you can rev them up then slam something over the top blocking air flow. This will clear a plugged jet quite often. Although it sounds like it is time for a rebuild. Make sure they add glue to the plugs so they do not leak. If the throttle shaft is worn, there is a kit you can buy to ream the bore and put bushings in.

Thanks for the compliment, but right now the Willys is in a thousand pieces in the garage Hopefully I can have it back together for next year. I cracked the frame and am replacing the frame with a custom one, along with tons of parts. Everything is being photo documented. For one of my buddies I dropped a built 350 and F&R Dana 44's into his 1969 Commando. Very nice rig I do not know the word "restore", seems like everything gets enhancements

Pour two cans of seafoam into the tank. I would do this before any extreme checks.
Seafoam can be found at a parts store.

Got the exact same problem on friends boat with a quadrajet.

Stripped carb, soaked it for a few days and rebuilt still same problem.

Going to look at some alternatives later this week.

I had the exact problem. would rev up fine but didn't run for crap. It would cut out and wouldn't accellerate and when it did it would sputter and fart. Took it to a carb shop, spent 150 clams. Haven't had a prob since. Take it to a speed shop they tend to have a better grip on quad's than most service shops.

Hey guys!
I have 2 problems with my 2001 Centurion Eclipse....1st off,vapor lock. We have bought a check valve and installed it. If the cover for the engine is left closed for...about an hour the boat will vapor lock about a minute after starting it. So what ends up happening, is we start up the boat, putt out to the river, and then it dies. If the motor cover is left open, we have no problem. We also have an electrical problem. My front nav lights (green and red ones) dont work, but if i have my stereo turned on, they glow a little. Can you help me? FYI:we have a bout 260 hours on it, and a merc. mag 350 mpi engine with 315 HP

mark- id check the fuel lines and see how they are routed. my guess is they are routed to close to the engine or a manifold and this is causing the gas to boil and vapor lock.

Thre have been several MErcury "Fixes" for vapor lock sine 01. Check with you local Mercury dealer about what you can do.

Good idea with the fuel line....We have tried a "fix" for the vapor lock. The "fix" what a check valve. We still get vapor lock. We are going to get the fuel pressure checked soon. To much or to little pressure could Cause vapor lock...right?

Thanks for your idea Alan

im not very knowledgeable on the issue, someone like rod is. but i think the only way pressure would be a factor is if your fuel pump isnt working hard/fast enough allowing the gas to sit in the lines and boil. but like a said i am very limited in my knowledge. if it was my boat i would find the gas lines and shield them for a quick test. get some hose of a larger diameter and cut it in half and slide it over the gas lines. if i was guessing this is probably the source of the problem.
the lights btw are and easy fix just isolate the positive to the switch. if need be even bring a dedicated p+ line from the battery. however that shouldnt be necessary just find a p+ under the dash and hook it up.

I don't remember all of the things that Mercury has for this problem but it seems like there where 3 or 4. I had a friend with a 2002 and Mercury paid for most of the fixes under warranty but there was one that he had to pay for. He never had another vapor lock problem.

You need to check with a knowledgeable Mercury mechanic and have him research the issue with Mercury