power surges at W.O.T

[cid1122]

Hello new to Iboats here with a bit of a problem with my boat. I have 1988 Four Winns Candia 200 with a 4.3L V6 OMC (chevy). Last time out, rite away I noticed it running rough at idle but when I hit the throttle all seemed great out of the hole but once on plane the power started to surge up & down (full rpm's to low rpm's). But at 1/2 to 3/4 throttle it would stop the surging but as soon as full throttle it would start again. Once off the lake I checked the oil and it seemed about 1 quart high and it smelled like gas. I have done nothing yet waiting for some idea's on where to start any help would be great. thanks

 

[Haut Medoc]

Re: power surges at W.O.T

Fuel pump has a ruptured diaphram. Do you have fuel present it the tube that goes to the carb? If so, time to change the pump.....oH, WELCOME TO IBOATS. Change your oil & filter, too......JK

 

[cid1122]

Re: power surges at W.O.T

thanks I'm at work but i will check that line 2marrow and see what i find

 

[cid1122]

Re: power surges at W.O.T

2 questions---- first to check for fuel in the line that goes to carb should I run it first then check it rite after I stop the engine or what should I do here. Second can I use an automotive fuel pump or is it best to get one made for marine. (4.3L chevy)

 

[rbezdon]

Re: power surges at W.O.T

Fuel pump and carb fall into the marine only catagory. They have two lines from the pump to the carb. 1 is the main steel line for feeding the fuel to the carb. The second is usually a smaller plastic one and sometimes is a clearish color. You can usually see through it so if there is fuel in it you might see it. This is the line that JK was talking about. You should be able to see it without running the boat again. It is VERY dangerous to run the boat if you have gas in the oil and in fact the engine will fail very quickly in this cindition so do not run it until the problem is fixed, and the oil and filter changed. This tube is also not present on automotive pumps. The tube takes fuel which enters the pump body and returns it to the carb to be consumed by the engine. Fuel in this tube can only come from a damaged fuel pump. The result is the extra fuel usually causes the engine to run bad getting you to fix the problem and the engine consunes the extra fuel instead of letting it drip off of the engine as a car would and accumulate in the bilge which is dangerous.

 

[cid1122]

Re: power surges at W.O.T

Ok I checked the clear line from the pump to the carb, some gas so I replaced the pump. After I replaced the pump I pushed in on the lever of the old pump and gas shot out of both the out valve and the one the clear tube conected to (this means pump was bad right) I then took it out for a test spin and the same thing good out of the hole but surged at W.O.T after on plane. so I then looked at the engine while was doing this and observed blue sparks from the area of the cap & wires when it started to lose power. guessing that it is bad wires/cap etc. again I ask car parts VS marine. Thanks for the help

 

[vipzach]

Re: power surges at W.O.T

I am one of the guys on here that says no car parts on my boat. The extra money they cost are minimal compared to my family and friends that could be severly injured or killed because I didn't want to spend extra money. Marine parts are designed to contain sparks, that way if you ever have a gas leak and go to start the boat, there is no boom. So please spend the extra money and get marine parts, when it comes to something concerning fuel or electrics on your boat.

 

[Haut Medoc]

Re: power surges at W.O.T

Go with marine parts.....If you had a car fuel pump or carb, with those sparks, you would probably be toast right now The extra cost of marine parts is well justified......Glad you didn't blow up, by the way .....JK

 

[cid1122]

Re: power surges at W.O.T

So I should assume that I have failing wires due the sight of blue arc's (correct.) If this is the problem I plan to replace the wires, cap, & rotor is there anything else I should consider or should I just start with the wires & plugs and eliminate from there

 

[Haut Medoc]

Re: power surges at W.O.T

Wires cap rotor should do it.....JK

 

[vipzach]

Re: power surges at W.O.T

I think replacing all of that would be a good place to start. Also replace fuel filters, check timing, spark plugs, general maintanence stuff.

 

[olbuddyjack]

Re: power surges at W.O.T

gas shot out of both the out valve and the one the clear tube conected to (this means pump was bad right)

Right.<br /><br />Even if it wasn't causing the surge, fuel in the clear tube means the diaphram broke.<br /><br />Don't forget to change the oil.

 

[rbezdon]

Re: power surges at W.O.T

I was going to add that too old buddy but the fact that you (*about time) were a quart high on the opil says there is a lot of gas in it. That engine wont last long if you havent changed the oil. Do IT BEFORE RUNNING ANY MORE!!!!! Especially with those spark running around. Heat will evaporate some of the gas in the oil making fumes and you will be toast of you dont change the oil priority ONE. And like I said, if you survive the engine wont. Gas in oil KILLS engines fast. Ask man of war what the gas in the oil cost him!!

 

[cid1122]

Re: power surges at W.O.T

I did not run the boat after I noticed the gas in the oil. I changed the oil and oil filter before I tested it the other night. Today I replaced the plug wires so I'll test it again tommarow and update everyone. this should fix the prob. because the guy I bought the boat from eairlier this year had 7mm car wires on and I bought 8mm marine (siera)

 

[cid1122]

Re: power surges at W.O.T

OK I replaced the plug wires and still the same results with an arc from the coil to the neg. post on the coil so I replaced the coil still surgeing at W.O.T could not tell if it was still arcing because it was day light. the wire where I had seen the arc runs to the distributer Its the neg. wire. Could it be the cap, rotor, points, or points condenser. Let me know what to do thanks

 

[cid1122]

Re: power surges at W.O.T

OK-- now it is just about completely dead. it will start but when you put into gear it dies. I still think its something to do with spark what should I look for now

 

[f_inscreenname]

Re: power surges at W.O.T

First of all, I will put my Accel (from Pep Boys) plug wires up against you Siera's any day. A good plug wire is a good plug wire and it does not have to say "marine" on it.<br /> As for your problem. <br /> When you replaced your wires did you put them all back on the right way? So easy to screw up. The best of us have done it. <br />You need to replace the points and set them properly, cap, rotor, spark plugs and see where that gets you. If you have been dumping fuel down the carb I bet the plugs are really shot. When you pull them tell us what they look like.

 

[cid1122]

Re: power surges at W.O.T

I think I'll just give up now and take it to a pro. instead of buying more parts that won't fix the prob. I'll post what the prob. is when I find out thanx for all your help