90 HP 1988 Mariner

[jjholland]

Motor starts fine but wll not run under load. It will somtimes run under load. I have replaced all the gas lines, rebuilt fuel pump, and cleaned carbs. Can anyone help.

 

[JB]

Re: 90 HP 1988 Mariner

Howdy, JJ.<br /><br />Hmmm. Wont run under load but sometimes runs under load.<br /><br />Can you be more specific? Is it down on power? What rpm do you get? What rpm is normal for your rig?<br /><br />Or does it just die (wont run) when you put it in gear?<br /><br />Let us know.

 

[jjholland]

Re: 90 HP 1988 Mariner

What I meant was that it has no power. I sound as if it is starving for fuel. I do not know the RPMs. I can be going along fine and then it just dies to the point that the boat will not plane. It will run like this for a few minutes and then it will take off at full speed again with out any changes on my part. It has been a progressive problem and now is to the point that it does not run properly more that it is running.

 

[dkondelik]

Re: 90 HP 1988 Mariner

'Mornin' jjholland,<br /><br />let's see if we can narrow down the possible sources of the problem. <br />Was the motor stored (for several months or more) with fuel in it?<br />When were the carbs serviced last?<br /><br />Is the pimer bulb collapsing or is it full and firm when the problem occurs. <br />Try squeezing the bulb when she acts up. If that doesn't help, carry a sqirt/spray bottle filled with 2-stroke mix (be careful with this), when she starts acting up, spray some 2-stroke mix into the carbs.<br /><br />This should tell you if/where there might be a fuel supply issue.<br /><br />Let us know what you find.<br /><br />Good Luck<br />HAVE FUN!

 

[pine island fred]

Re: 90 HP 1988 Mariner

for what it is worth. just had the same problem with my new merc out of the box. mid range or above the engine would hunt and had a mind of its own. found the fuel line really kinked where it and the control cables enter the motor. found it before it went back to the dealer.

 

[jjholland]

Re: 90 HP 1988 Mariner

Thanks Guys<br />To give you some more info I have cleaned the carbs for the past 2 years. I have tried squeezing the ball while it is bogging down and that does not have an affect. The ball does not collapse. I talked with a machanic at a dealer and he told me it should not be the carbs because it changes from not running to running bogged down and back again while I am on the water (more not running). I will try the fuel in the spray bottle and see if it that will narrow down the problem.

 

[Valv]

Re: 90 HP 1988 Mariner

JJholland, I would invest in a gauge and check compression. It is a very inexpensive tool and will tell you A LOT of your motor. If you have bad compression on 1 cylinder, it is a waste of time looking for other problems.<br />It's one of the few necessary basic tools to work on motors, and I never did regret buying it, even a cheap one will do the job ($ 35.00).