need help with an olds 455 problem

[dave7887]

im kind of new to boating. i just got my first boat, its a 1970 tahiti with an olds 455. we took it out this weekend to elsinore because the weater was bitchin. but anyways, the boat idles fine and puts around slow, but as soon as i punch it and get on the gas it just craps out and the motor dies. it will start right back up after that. any sugestions?? thanks guys

[jetboat=$]

i had the same problem...i hate to tell you this but it sounds like a cracked block. what color is the oil?

[sleekcrafter]

Sounds like maybe a bad accellerater pump, or it's disconnected some how. Other things could be lack of fuel pressure, low floats in the carb, timing off.
Just things to check.
Sleek

[Wet Dream]

Kinda harsh going for the cracked block theory right off the bat aren't you? How about fuel pressure, float levels, blocked filter, stuck secondaries, bad gas, squirters blocked off, bad fuel pump? Borrow a good carb and try that and go from there. Check the oil for oil, or is it looking like a milkshake?

[76ANTHONY]

what carb you got on it? i have an extra carter you can borrow, its only a 550 but it moved my 455 pretty good...

[jetboat=$]

not trying to hurt feelings here but that was my problem. thats why im not a mechanic, i always look for the worst possible and get pissed off about it.
at what rpm does it cut out?

[sleekvino]

i would bet that it is water in the gas, remove a fuel line and dump it in one of your wifes good glasses and see if water is at the bottom of it.if you have alot then just hit the carb wihle your looking down it and see if theres water drops in it.if there is ,get some water remover "nuheat"for the tank and get a fuel water separater.good luck. :cool:

[Rocknpalms]

I had the same problem, fortunatly all I had to do was reem out the main jets a few sizes. Sounds like a lack of fuel. I would first make sure the ecelerator pump is working and that the ecelerator cam size is not too big or small (I have the white cam in mine), check the float level, install a fuel pressure gauge. If all that is fine make sure the secondaries operate correctly and then look into the main jets. Just my .02

[Taylorman]

not trying to hurt feelings here but that was my problem. thats why im not a mechanic, i always look for the worst possible and get pissed off about it.
at what rpm does it cut out?
Good thing your not a mechanic the way you troubleshoot. I'd hate to see what you would have said if he had no oil pressure.

[jetboat=$]

id tell him to smack the hell out of the gauge!!!! and after your hand hurts check the oil

[maxwedge]

Will it accelerate normally if you ease into it or does it just not get up to speed at all? If it's the later, my 455 had a bad ignition coil that acted like that. Idle was near perfect, ran fine with no load but as soon as you put any load on the engine it would die (just as it was about to come up on plane). I swapped out the fuel pump and went out a few times with no problems. Second time it happened I swapped the coil because I had one with, thinking that it probably wouldn't make any difference and the fuel pump had gone bad again, but it fixed the problem. I would check the coil and the fuel pump pressure first, before you start switching carbs and engine blocks. :) If it only dies when you really hammer it, then I would look into other accelerator pump/carb problems.

[1899]

Sounds like your carbs arent keeping up with fuel demands. They could be clogged (like my jetski was, fuel cleaner fixed the problem) or floats not adjusted properly. These motors drink, No, gulp alot of juice. I personally would try running some Lucas injector cleaner thru there first, its only $3-4.

[malcolm]

Maybe we need some more input here. What carb are you running? So far just sounds like a lack of fuel. Can you rig up a fuel pressure gauge on it and see what happens to it when you hit the gas?

[Sleek-Jet]

I'd look for a plugged fuel line, check fuel pressure, check fuel filter, and if all else fails, clean the carburator real well. Maybe the accelerator pump isn't working (plugged or diaphram is bad)???

[dave7887]

damn so many responses since ive been back. well lets see where do i start, first off i have a rochester quadrajet carb im not sure of the size exactly. it idles fine and if u punch it it moves like a bat out of hell but only for like 20 seconds then it craps out. it has a new fuel pump and filter, it has a fuel/water sepporator. what is an accelerator pump? and what would happen if the block was infact cracked? and how would i tell if it was? ive seen a little water squirt when i haul ass. i think i need to just get a fresh carb and go from there but then again i have no clue. thus why im asking the pros. well maybe that can narrow it down a little. thanks

[sleekcrafter]

damn so many responses since ive been back. well lets see where do i start, first off i have a rochester quadrajet carb im not sure of the size exactly. it idles fine and if u punch it it moves like a bat out of hell but only for like 20 seconds then it craps out. it has a new fuel pump and filter, it has a fuel/water sepporator. what is an accelerator pump? and what would happen if the block was infact cracked? and how would i tell if it was? ive seen a little water squirt when i haul ass. i think i need to just get a fresh carb and go from there but then again i have no clue. thus why im asking the pros. well maybe that can narrow it down a little. thanks
Good more info, narrows it down, sounds like fuel problem for sure but you never know. Check the tanks, thee are check valves on them, they can become plugged from debris from over the years, also check the pick up in the tanks, make sure they are not cracked. One last things double check you fuel filter, make sure it's no backwards. Good luck Sleek

[GunninGopher]

I am by no means an expert here, but I just bought a boat that had that same problem as you describe in your first post. I got it home and found the secondaries were stuck dead shut. I couldn't even knock them loose. I had the carb rebuilt and it we'll see how it turns out. This boat hadn't seen much use over the last couple of years.
I'd guess that most posts here are correct and you are probably just not getting enough fuel, since your last post seems to indicate that you are getting good performance for a little while.

[Duane HTP]

Sounds like your carburetor is working okay as long as it has fuel. If it was the accelerator pump, or water, it would not take off and run good for the 20 seconds. Check your filters first. Change out the water seperator filter. Put a fuel pressure gauge on it and find out if it is in fact running out of fuel pressure. If so, then it's time to find out why. Could be lines, pump, or like others said, the check valves at the tanks or the pick up tubes in the tanks. Good Luck.

[malcolm]

I still run a Quadrajet too. Most of them were 750s. I like 'em. Hell, mine ran great without the accelerator pump even working! :D It's that thing that the little rod and lever goes to on the top. They don't hold a lot of fuel, so they need a good volume of gas to keep running @ wide open throttle. I had a problem with junk in one of my tanks getting sucked into the pickup tube. I finally noticed that I only had the problem when I singled out to the left tank.

[kcsteck]

I have had same problem, for me it was crap in the tank and the fact that the tubes fell of in the tank to pick up the fuel as well. there are many things it could be.

[Red Horse]

Sounds like fuel delivery problem as other have said. Water in the fuel. On my jetboat I have 2 tanks. From each tank I run one of those fram G-22 clear filters and have it set at an angle. They are cheap to replace (2-3 bucks) and at an angle will allow water to go to bottom and fuel to pass plus you can see it. Right before the carb I have a clear glass filter as well. Having a few of these on the boat has meant the diff between a paddle back, trailer home scenario or a great day on the water. Reduncy is the key to happy boating!! :cool: