Motor Problems

[David Massey]

Hey All,



I went out and fished the last 3 days for a tournament. When idling at the weigh in on Saturday evening, the motor was idling rough and died when I put it in reverse a couple of times. On Sunday morning, it had a hard time starting. It seemed the only way to get it to start was if I put the throttle up a little in the neutral position and then it would fire. I had to back it off slowly then go to neutral then forward before it had a chance to choke out. Again at weigh in it died at idle and when I put it in reverse.



I am hoping that it is just spark plugs or maybe a fuel filter but I am not sure. What do you all think it may be? Please help.



By the way, to top it all off, my partner and I had a terrible tournament.

 

[Dan J.]

Sounds like typical fouled plugs on a two stroke, but without any more info I'm in the weeds there with ya. Your profile shows only a hull and engine info is what you're wanting.

 

[Randy Walls]

My buddy had a very similar problem and put new plugs in, new fuel filter and ran some Mercury carb and fuel system cleaner through it. Has never had the problem come back since.



I have now also talked him into using the marine stabilizer in his fuel to help.



Hope yours is as easy to remedy!



Randy!

 

[David Massey]

Hey Dan,

The motor is a Mercury Mariner 150 EFI. I believe it is a 1999.

 

[Dan J.]

It deserves a cleaning at minimum or new plugs (NGK BU8H) yearly. It's a cheap investment to keep that carbon on the move out of your cylinder head. Full combustion is the only combustion you want on a two stroke. If your filters are old or yellowed out and dark looking inside the filter, change those in-line and check the filter screen before the injector pump assembly. Run a dose of Quikleen next fill-up and you should note a difference when added to the above maintenance. Good luck!

 

[David Massey]

OK So here is the update. I talked to a relative of mine who's family owns the boat dealership here in town, and he had a tech look at it for me. They hooked it to a computer and everything checked out great but it obviously was still running poorly. The tech had an idea an took the front of the motor off and sure enough, found that one of the reeds had broke.



It is being fixed now and I should have it back in a day or two. Thank you for your responses. I got lucky on this one and it is going to be a cheap fix. Kudo's to the tech that figured out the problem.

 

[Dan J.]

Since you have the access, have the tech scope the cylinder(s) and make sure any broken reed pieces are retrieved, if not hopefully already passed through the exhaust port. Once you find the broken reed you owe it to yourself and your powerhead to makes sure the block is debris free. A broken reed has seized pistons, sending a rod through the block, too many times. Glad to hear you have a good wrench on top of it!

 

[Rob LaMoy]

I have a 99 175 efi. They are cold blooded and run choppy with any bad gas or plugs. Like everyone said, clean or change your plugs, put in some Ring free or Merc carbon remover or Merc injector cleaner, then top off the tank with fresh gas and run the snot out of it for a few minutes. Should do the trick. Also, if it's never been done, change the fuel filter. They are under $20 and it's right under the cowling on the driver side. Just pull off the sensor wire on the bottom, unscrew it, and then reverse the process with the new one.