1997 Mercury 225

[TimmyTodd2]

So the boat gets on plain quick and the engine runs great up to 3,800rpm, if I try to run faster the boat will bogg down and the rpm's get erratic (go down then come up, then go down and come up, etc). If I back off to 3,700rpm the boat runs fine. I replaced all the spark plugs today and gapped correctly. Any suggestions? Thanks for the help in advance.

 

[TimmyTodd2]

Re: 1997 Mercury 225

I believe the Primer Bulb is the problem. Such a small and inexpensive part could be the issue, wow.

 

[j_martin]

Re: 1997 Mercury 225

I believe the Primer Bulb is the problem. Such a small and inexpensive part could be the issue, wow.

WHY..... do you believe that?

 

[islandcruiser]

Re: 1997 Mercury 225

I believe the Primer Bulb is the problem. Such a small and inexpensive part could be the issue, wow.

I had the same problem the other day as well, but mine got progressovely worse. It started out the same as you described but then it seemed to have dropped a couple of cylinders but only eraticly. Sometimes I could get on a plane and other times it wouldn't go above 2200 rpm. My boat does not have a primer bulb as I believe the fuel pump on the engine takes care of that. When I removed the spark plugs a couple of minutes after the problems, most of them were wet with gasoline, but looked normal other than that with a little bit of black on the outer ring. I am going to check the coils for spark later this week to see if any of them have failed. Any help would be appreciated, and good luck to you TimmyTodd2.

 

[TimmyTodd2]

Re: 1997 Mercury 225

I talked with a good friend that knows engines really well and he asked if my Primer Bulb was squeezed together, flat (i.e. bad primer bulb would prevent gas flow intermittent and especially at high RPM's). Sure enough it was flat. Only $9 for a new one so will be replacing this weekend and hope it works. Can't hurt for $9. Did the rpm's surge pretty bad? If you don't have a primer bulb, maybe the fuel pump is going bad? I'll check with my friend and see what he says. Good luck!