Bogging Problems?

[ProfitOfDoom]

Well the other day I was out and it bogged on me a couple of times "didnt shut off" but it seems when I gun in fast or press my throttle to far open I get this where it boggs just doesnt want to run,its fine if you bring it back down and bring it back up slower.
What could this be?
Could it be water in the fuel? I looked around and didnt see a water/fuel separator,think this is it?
I got the boat with close to a half tank already in it,which sat I all winter,I see a bottle of fuel stabilizer that the PO had so im assuming it was used,Im not sure what grade of gas he used but I added 15 gallons on regular on top of his say 40gal. Could it be this engine doesnt like low grade?
When I start it up after it hasnt run for a couple of days or so,I prime it with about 5 pumps of the throttle it will fire right up run a few seconds then it shuts off,a few more pumps of the throttle then it starts up and keeps going,I just thought this might help trouble shoot.
There is also a fuel filter canister I could replace if you think that is the problem,If you have any ideas on what it could be let me know,Thanks

 

[MCLKS]

At risk of starting a Ethanol debate, I too just recently experienced a similar situation and then a low pressure fuel pump failure. After emptying the fuel filters there was only a very small trace of water. There was however a film of "slime" like gel that was believed to be the Ethanol separation issue. This is after five months on land for the winter.

Prior the layup period, the gas was treated including throughout the season. What was most interesting is taking a clear glass and dumping your filter then letting it sit outside on a humid day for two to three hours. You will actually see the Ethanol attracting moisture.

Please note that many gas treatment also contain alcohol based products for cleaning and attracting moisture - you need to read the lables.

As for grade of gas - most marinas supply mid and high grade only given that most marine engines need 89 or better octane to perform to their maximum potential.

 

[33ec]

I had a similar situation om my previous boat--changed fuel filters -both of them. the in line canisters as well as the small paper element filters instie the carb. if you have rochester carbs, they are inserted in the fitting where the fuel line attaches to the carb. clean filters solved the problem for me. . the engine was starving for fuel when I gunned it. good luck

 

[Quint4]

If you don't get lucky with the filters it sounds like carb rebuild time. If you buy a rebuild kit it will contain an accelarator pump (small plunger type mechanism that lives in your carb) this may be your problem. I bought a rebuild kit last season for around $100 and did mine. You need a manual. I laid a clean sheet on a table in the garage and did it in about an hour or so. Work environment needs to be clean! If it does not fix the problem it is still money well spent on your older 454.good luck with it.

 

[ProfitOfDoom]

Ok,well sounds like the filters could be my problem and since that will be the easiest and cheapest I'll try that first. When I unscrew the filter,Im not sure what to expect,Will gas keep dribbling out until the new filter is in place or what? Also on my older boat it had a few/water separator and they said fill it with gas before installing to make it start quicker,Same rules apply to this filter?
I will put better gas in it,but as of right now I still have around 20-25 gallons in it,Should I just add the better gas right on top of it,or try to run out most of the old gas before I change filters and add new gas?

 

[JVM225]

I just had this exact same problem last week.
I had one bad carb, so I ordered two rebuilts and put them on my motors. I always figure when something goes bad on one motor, the same part on the other motor is usually close behind.
Anyway; my port motor was bogging after I installed the new carbs and I couldn't figure out what it was. I had my friend, who is a great mechanic. ride in the cockpit with the hatches above both motors removed and the flame arrestors off. He found my problem right away.
The butterfly for the secondaries on the one motor was getting stuck in the open position when I accelerated and causing the motor to bog. We bent the rod slightly to prevent it from going all the way back and locking the butterfly open, and the problem was solved.
I'm not sure if the rod was slightly too long, or the slot it rides in was down too deep, but the rod was going to far back and locking.

 

[ProfitOfDoom]

I will also check that,Could I just have someone play with the throttle when the boat is not running to see if it is sticking or not?
I went down to my boat have today to get a number on the fuel filter and was wondering Could I replace the standard screw on filter with a water separator filter,or are these 2 different things?

 

[chumbley]

My money is on the accelerator pump.

 

[Gunn]

Accelerator pump here too. When you pump the throttle five times and it starts, you're throwing a lot of gas into the carburetor. It dies because the gas you pumped in burns off and the gas in the fuel bowls of the carb can't keep up with the demand. Similiar thing is happening when you open the throttle quickly.

If you're secondaries on the carb are vacuum operated, you can't have someone eyeball it while it is not running...they won't move.

You could add a fuel filter / water seperator ahead of the carb...I have done that. You could replace the one you have, or just have both.

Carbs are easy to rebuild, just pay attention (and take pictures if need be) of how everything comes apart so you can put it back together the same way!

Tom

 

[tmccoy6]

My boat sat for almost two years between use. Before I attempted a start I added Octane booster, then put Supreme on top of that. I ran it this weekend with no issues, so it could be just bad gas.
As a rule of thumb also ways go with higher grade fuel, it does not cost that much more and if you dont use the boat very much it sure helps.
I winter my boat in Texas so I do not have the cold weather problems that many of you do thus I can not speculate further.
Also did you replace the fuel filter? Might do that as regular maintainence.