help please

[MMassassian]

Hello everyone, Been reading the threads trying to find an answer to my problem. I have read other people's post that are close to mine but not the same....

I have a 1989 supra comp boat that I just bought a few weeks ago. The 1st couple of times out, no issues boat ran awesome. But the last 2 times we have taken it out when I maintain the same speed the boat dies. I have to speed up then slow down to keep the boat running. It doesnt do it all the time though which has my confused where to start and what to look for. thanks for all the help

[Mani]

I'd say first thing to check would be the fuel and air. Check the line for kinks and other obstructions, check the fuel filter, and change it out if you can. Basically make your way over to the carb.

Basically start with the easy stuff, first.

[MMassassian]

I'd say first thing to check would be the fuel and air. Check the line for kinks and other obstructions, check the fuel filter, and change it out if you can. Basically make your way over to the carb.

Basically start with the easy stuff, first.

okay...Im at work right now, but will be off in a few hours. So doing some research on what to check..thanks for the help.

[MMassassian]

is there a place I can download the manual for this boat? that would help me out a lot

[sybrmike]

Try the "the library" tab under "community" on this board. I think they go back to 90.

[fastab]

Being you just bought the boat, You should replace the fuel/water filter, stock was on the port side just below the front of the engine. Oil should be replaced(this shouldn't have an effect on running just general maintanence)
spark plugs check/replace, Check distributor cap, rotor, see if it still has points. If it does you may want to convert to electronic ignitions. Also what condition is the impeller, I would replace it as you don't know how old it is unless you changed it already.
What was the engine temperature at when you were running and when you had the problem.

When you bought it did you do a compression check. I would do a compression check it is a quick test of the engines internal condition.

You need to know that you have good compression on all cylinders, good spark (ignition system) Clean fuel/supply. These steps may help you to isolate one of the systems that you need to look at.

[MMassassian]

Being you just bought the boat, You should replace the fuel/water filter, stock was on the port side just below the front of the engine. Oil should be replaced(this shouldn't have an effect on running just general maintanence)
spark plugs check/replace, Check distributor cap, rotor, see if it still has points. If it does you may want to convert to electronic ignitions. Also what condition is the impeller, I would replace it as you don't know how old it is unless you changed it already.
What was the engine temperature at when you were running and when you had the problem.

When you bought it did you do a compression check. I would do a compression check it is a quick test of the engines internal condition.

You need to know that you have good compression on all cylinders, good spark (ignition system) Clean fuel/supply. These steps may help you to isolate one of the systems that you need to look at.


thank you for the help...I already had all the fluids replaced when I bought it, and Ill check the rest today. It just seem weird that I had to feather the throttle to keep it running smooth...that if I ran it at the same speed for more than 5 seconds it would bog and then die, but start right back up.

[fastab]

thank you for the help...I already had all the fluids replaced when I bought it, and Ill check the rest today. It just seem weird that I had to feather the throttle to keep it running smooth...that if I ran it at the same speed for more than 5 seconds it would bog and then die, but start right back up.

Just another note after reading this reply, Feathering the throttle maybe an indication of starving for fuel, The carb has a acclerator pump on it that will pump fuel each time the throttle plates are opened as soon as you stop it stops pumping fuel. It maybe a fuel supply problem or problem in the carb more than likely problem in the carb as the accellerator pump wouldn't have fuel if the carb wasn't being supplied with fuel.

When you check the fuel filter check for water, if there is lots of water there could be some in the carb(float chambers) water is heavier than gas and will sit in the bottom. Water doesn't flow the same as gas and can plug the jets enough to cause irratic running, when the engine shuts off the vacum stops and the water settles back to the bottom of the chamber. Dirt can do the same, depending on the style of filter if it is a metal canister I have seen them rust from the water sitting in them and this getting into the carb.

If you see water and rust in the filter I would drain the float bowls into a clear cantainer like a pop bottle, the only thing that should come out is clean gas anything else is a problem. You may need new gaskets for these bolts so you may want to find a carb kit before you do this. If it is a Holley you will need the numbers off of the side of the carb List, etc. I would go thru and check the first stuff first.

[rludtke]

Just another note after reading this reply, Feathering the throttle maybe an indication of starving for fuel, The carb has a acclerator pump on it that will pump fuel each time the throttle plates are opened as soon as you stop it stops pumping fuel. It maybe a fuel supply problem or problem in the carb more than likely problem in the carb as the accellerator pump wouldn't have fuel if the carb wasn't being supplied with fuel.

When you check the fuel filter check for water, if there is lots of water there could be some in the carb(float chambers) water is heavier than gas and will sit in the bottom. Water doesn't flow the same as gas and can plug the jets enough to cause irratic running, when the engine shuts off the vacum stops and the water settles back to the bottom of the chamber. Dirt can do the same, depending on the style of filter if it is a metal canister I have seen them rust from the water sitting in them and this getting into the carb.

If you see water and rust in the filter I would drain the float bowls into a clear cantainer like a pop bottle, the only thing that should come out is clean gas anything else is a problem. You may need new gaskets for these bolts so you may want to find a carb kit before you do this. If it is a Holley you will need the numbers off of the side of the carb List, etc. I would go thru and check the first stuff first.


Yup to everything Fastab stated. I wanted to add that low float bowl settings could contribute to this condition, as could sticking needle valve (sticking closed and opening late). The result of both is float levels not high enough to support extended operation at that power setting. Wiggling the throttl will pump extra fuel out of the accelarator pump, giving the engine what it needs for a moment. Also, when the engine slows down, so does its fuel flow requirements, allowing the float level to catch up a bit, albeit temporarily. Restricted fuel flow to the carb could also cause the float level to run down and not keep up with the engine, so check the carb inlet screen, and the fuel pump. In case it is a sticking needle valve, I recomend overhauling the carburator.

[MMassassian]

wow thanks guys..Ill keep everyone update as I work my way thru this. Thanks again for all the help