Hi all! First post here. I am fairly mechanically inclined but know next to nothing about boats. I have a mercruiser 470 with an Alpha One drive. Everything was redone in 08' by the previous owner(entire motor and drive rebuilt). I have had the boat for 4 years now but have had to do very little to keep it in working order aside from regular maintenance . Despite the negative things I have heard about this motor I have really enjoyed owning this boat once I got used to it's quirks. No major issues until now except a bad throttle controller.
The last time I had her on the water (last fall) we were having a good day. No issues what so ever with the boat all day. I start her up for the last time to head home everything starts up good. No noises or anything. We exit the no wake zone and I start to give her some gas. Just as were getting up on plane we smell a slight burning smell. As though someone is burning plastic or rubber. Because of our surroundings and how quickly the smell went away I assumed it was something coming from shore. About 30 seconds later we start rapidly slowing down. The motor never shuts off or makes any kind of noises and I didn't detect any further smells but it will not shift at all. Forward or reverse. I can give it throttle just fine but the drive will not engage. We had to find a tow off the lake (not an easy task that time of year, that late in the evening where we are) This was very late last fall and I did not attempt to diagnose the issue further or run it on the muffs. Just put her away for the winter. The only thing I can think that I've done that may have had any kind of effect on this is I replaced the throttle controller last spring. This was not the first time on the water with the new controller though.
Now we get to this spring. I pulled the boat out of storage last week to start diagnosing the issue and get ready for the coming summer. The first thing I did was get set up with the muffs to see if she still runs fine(I know this was probably not what my first step should have been). Started right up as though we were already on the lake no problem. I pop my head over back to make sure the muffs are still on properly and I notice there is no water coming out of the exhaust. I immediately check the temp gage, still not hot enough to register but I shut it down anyway. At this point I do some(very) quick research on my phone and don't come up with much. What I did next I, again, am fully aware was probably not the right choice. I decided to start the boat up again and just keep a close eye on everything to see if the water will start circulating on its own. The temp gage never moved (maybe slightly) but after about a minute of running at about 1/4 throttle I here cracking or crackling from the engine bay. I immediately turn the motor off. The "cracking" sound continued for about a minute and there was a burning smell and a decent amount of smoke or steam(not sure which). The sound and the smoke or steam was(and I believe the smell) coming mostly from somewhere between the transom and the back of the motor(on the heat exchanger side). There was also some smoke/steam coming out of the front of the heat exchanger between the cap and the exchanger itself. I am not certain (don't entirely recall what it looked like before the incident) but I believe the cap on the front of the heat exchanger is slightly bent out all the way around the outside edge as though there was an excessive amount of pressure inside the heat exchanger. I will post a pic of this later today or tomorrow.
I am wondering if these two issues could be related?
Sorry for the long winded post. If anyone has some insight about where I should start here I would really appreciate it. Thank you.
The last time I had her on the water (last fall) we were having a good day. No issues what so ever with the boat all day. I start her up for the last time to head home everything starts up good. No noises or anything. We exit the no wake zone and I start to give her some gas. Just as were getting up on plane we smell a slight burning smell. As though someone is burning plastic or rubber. Because of our surroundings and how quickly the smell went away I assumed it was something coming from shore. About 30 seconds later we start rapidly slowing down. The motor never shuts off or makes any kind of noises and I didn't detect any further smells but it will not shift at all. Forward or reverse. I can give it throttle just fine but the drive will not engage. We had to find a tow off the lake (not an easy task that time of year, that late in the evening where we are) This was very late last fall and I did not attempt to diagnose the issue further or run it on the muffs. Just put her away for the winter. The only thing I can think that I've done that may have had any kind of effect on this is I replaced the throttle controller last spring. This was not the first time on the water with the new controller though.
Now we get to this spring. I pulled the boat out of storage last week to start diagnosing the issue and get ready for the coming summer. The first thing I did was get set up with the muffs to see if she still runs fine(I know this was probably not what my first step should have been). Started right up as though we were already on the lake no problem. I pop my head over back to make sure the muffs are still on properly and I notice there is no water coming out of the exhaust. I immediately check the temp gage, still not hot enough to register but I shut it down anyway. At this point I do some(very) quick research on my phone and don't come up with much. What I did next I, again, am fully aware was probably not the right choice. I decided to start the boat up again and just keep a close eye on everything to see if the water will start circulating on its own. The temp gage never moved (maybe slightly) but after about a minute of running at about 1/4 throttle I here cracking or crackling from the engine bay. I immediately turn the motor off. The "cracking" sound continued for about a minute and there was a burning smell and a decent amount of smoke or steam(not sure which). The sound and the smoke or steam was(and I believe the smell) coming mostly from somewhere between the transom and the back of the motor(on the heat exchanger side). There was also some smoke/steam coming out of the front of the heat exchanger between the cap and the exchanger itself. I am not certain (don't entirely recall what it looked like before the incident) but I believe the cap on the front of the heat exchanger is slightly bent out all the way around the outside edge as though there was an excessive amount of pressure inside the heat exchanger. I will post a pic of this later today or tomorrow.
I am wondering if these two issues could be related?
Sorry for the long winded post. If anyone has some insight about where I should start here I would really appreciate it. Thank you.
