longshanks
Petty Officer 2nd Class
- Joined
- Jun 12, 2006
- Messages
- 188
Hey folks
So I am the owner of the above motor, which was purchased from a saltwater fishing resort this spring. The motor has compression of 180 on all four cylinders, 23.7 hours of run time, and hooking it up to Merc's computer shows that it was rarely run above 1500 RPMs for its life thus far (in salt water). I bought it, expecting it to be a fairly new engine, that would provide reliable service for my boat. Plus, it's under warranty until '08.
I'm fairly surprised and disappointed that I have only been able to use the motor twice, very briefly, and on both occasions, the motor has beeped out an overheat alarm, as I rev the throttle up. Motor seems to be pumping water just fine, and although the water is not getting overly hot, the top end of the motor cannot be touched, and mercury's computer hook-up verifies that the motor has been overheated 2x, for up to 4 minutes, on these occasions.
My mechanic has replaced the impellor, which was slightly worn, and checked the thermostat ($300 later). Everything appears to be functioning normally, but the motor is overheating before it can even be opened up. There is lots of oil in it, and I believe the mechanic did a backflush to ensure nothing is trapped in the motor. I will verify this shortly.
I've been doing a little research, and I find that there have been a number of problems with some of the (especially older) merc 4-stroke 50's overheating in this very same manner. It seems that between the powerhead and the lower end of the motor, there is a metal water tube that can corrode, constricting a grommet, which restricts water flow to the power head, resulting in overheat. Merc apparently paid for some of these repairs, but I'm asking myself, could this problem still persist in my 'nearly new' motor, made about 8 years after the early generation motors?
I am presently waiting for a mechanic to have a look at my motor, but I thought I'd ask if any others have experienced this problem, or if anybody has advice for what I should be looking for. Also, what are the odds of problems caused by these overheats? Compression remained unchanged after the first one, which was around 4 minutes.
thanks in advance for your help
cheers
longshanks
So I am the owner of the above motor, which was purchased from a saltwater fishing resort this spring. The motor has compression of 180 on all four cylinders, 23.7 hours of run time, and hooking it up to Merc's computer shows that it was rarely run above 1500 RPMs for its life thus far (in salt water). I bought it, expecting it to be a fairly new engine, that would provide reliable service for my boat. Plus, it's under warranty until '08.
I'm fairly surprised and disappointed that I have only been able to use the motor twice, very briefly, and on both occasions, the motor has beeped out an overheat alarm, as I rev the throttle up. Motor seems to be pumping water just fine, and although the water is not getting overly hot, the top end of the motor cannot be touched, and mercury's computer hook-up verifies that the motor has been overheated 2x, for up to 4 minutes, on these occasions.
My mechanic has replaced the impellor, which was slightly worn, and checked the thermostat ($300 later). Everything appears to be functioning normally, but the motor is overheating before it can even be opened up. There is lots of oil in it, and I believe the mechanic did a backflush to ensure nothing is trapped in the motor. I will verify this shortly.
I've been doing a little research, and I find that there have been a number of problems with some of the (especially older) merc 4-stroke 50's overheating in this very same manner. It seems that between the powerhead and the lower end of the motor, there is a metal water tube that can corrode, constricting a grommet, which restricts water flow to the power head, resulting in overheat. Merc apparently paid for some of these repairs, but I'm asking myself, could this problem still persist in my 'nearly new' motor, made about 8 years after the early generation motors?
I am presently waiting for a mechanic to have a look at my motor, but I thought I'd ask if any others have experienced this problem, or if anybody has advice for what I should be looking for. Also, what are the odds of problems caused by these overheats? Compression remained unchanged after the first one, which was around 4 minutes.
thanks in advance for your help
cheers
longshanks
