Merc 80hp - No water pumping on restart

[dceonline]

Hi -
'72 Mercury 800 - well maintained but stored last 2 years. Took it out and it started & ran great - very quiet idle for a 2-stroke, and very smooth runner. Consistently kept close eye to make sure its pumping water (which it was). After a couple of runs, had it idling a bit (still pumping water albeit not as smooth a stream - I was really keeping an eye on this), and then shut the engine off. Maybe 5 mins later went to restart and it started to idle, but died when shifting into gear. Tried starting again and while it idled I checked the p-hole hole and no water coming out, so just cut it and trolled her in. There was no smoke / smell / or other obvious indication of overheating.

At the shop, I asked them to check the motor over. They checked it out, and said water pump appeared to need replacement, but said there wasn't any scorching and they didn't detect any other damage. Replaced the pump and said motor started great and ran great. Said they didn't see any other issues.

Before we take it back out on the lake though, wondering if it makes sense that the water pump failing would cause it to react in the manner described above. I mean, I'm sure the water pump needed replacing just due to the time stored - but wondering if there might have been a different issue that could have contributed to the problem that the shop isn't seeing. I thought that if the pump failed, the engine could still function (shift into gear, etc) - it would simply overheat quickly and create damage. I guess I just don't understand how the symptoms point to just a water pump replacement, and now everything is running great again.

I should note that I didn't try priming the bulb to see if it was fuel related as the lack of water coming out the p-hole while at idle made me decide to kill the motor vs. messing around w/possible overheating. I also understand that this motor has no 'tone' for overheating so that doesn't help either. A friend thought that maybe it wasn't getting enough gas and therefore wasn't driving the pump enough to push water out the p-hole - but shouldn't idling be enough to make this happen?

Any thoughts appreciated. Thanks.

 

[Clams Canino]

Re: Merc 80hp - No water pumping on restart

Waterpump needs to be changed every 2nd season AT WORST. To even start it after 2 years of storage required replacing the pump FIRST - and that's assuming it was changed the day before it was put away.

You may have some idle adjustment / low speed issues to deal with - but replacing that neglected waterpump was a needed (and late) 1st step.

-W

 

[dceonline]

Re: Merc 80hp - No water pumping on restart

Hi, thanks for the response. According to supplied paperwork, the pump & impeller were last replaced in October '04, along with carb service and winterization, and then the boat was stored. Being new to this, we took this to mean that the boat was going to be good to go. It is definitely a lesson learned. We did talk to a shop about it before taking it out, and were told to keep a close eye on the peehole, which we did. I have become very aware now at how important 'idle time' is when it comes to internal boat parts. When I look back through the paperwork, the previous owner seemed to have most of his maintenance done at the end of each season when he had it winterized. I suspect this had something to do with the remote location of the lake the boat was run on.

Hopefully my ignorance hasn't caused any damage. That is in part the reason for this question to begin with. Knowing now that I assumed incorrectly on the pump, what else am I missing? The shops out here are very 'get it in and get it out', not a real hotbed of advice. I purchased a Seloc manual for this motor, and have gone through messages on this forum and have pieced together things I can do / look for. What scares me the most about this motor is that the pump or impeller could fail at any time, whether it's new or not - and the only way I'll know about it (before the real obvious signs like thick black smoke) is whether or not it's spitting out water?? Wouldn't do much good at 30+ mph when it's not really feasable to be driving and looking at the motor. If it's true that this motor has no sound indicator, then I guess I need to have some additional indicator added.

 

[Clams Canino]

Re: Merc 80hp - No water pumping on restart

Also make sure the carbs aren't gummed up. Idle needles outta have desired effect and WOT outta hit.

As for the pump... if it's pissing good at idle when you start it, assume it's OK for that day... assuming is < 2 years old.

-W