Mercury engine maintainence

[briangeorge]

I own a 2015 Mercury 150 H.P. Engine. It says in Owner's Manual to do the following after 300 hours or 3 years.
1. Change out Impeller
2. Change out Alternator Belt
3. Change Spark Plugs
I think this is overkill just wondering what everyone else thinks about this.
I checked the alternator belt and spark plugs yesterday and they look like new. As far as impeller I would have a dealer do it when time comes.
Thanks everyone.

[TROLLER]

My experience has always been with my boat and truck, maintainence is the cheapest thing you can do. If you look on face book you will find it is not difficult to change out the impeller. I changed mine out at 350 hrs and it really did not have a lot of wear. As to the drive belt, just take it off and take it to any auto parts store they should be able to match it up. Way cheaper than buying from Merc. and cost around 20 bucks. Cheap insurance.

[briangeorge]

Thanks Troller for the advice.

[SamSteele]

As Troller mentioned, the maintenance is cheap insurance. This is especially true when you have warranty remaining. Merc had the 3+2 warranty recently, so you may still have some on your 2015. I know that started in 2016, but can't recall if it was around in 2015.

A water pump failure due to impeller is not a fun experience as it always seems to happen far from the dock on a rough water day. To me that is the most critical of the three listed.

SS

[fordtruckin]

I have a 75 merc on my boat for work. The prior guy who it was assigned to got it when it was brand new. Right now it’s 9 years old and sad to say in those 9 years it had never had any fluids or maintenance done until it was assigned to me. I went without the boat for most of last summer because I had to get caught back up before I’d take it out. I guess my point is, yes going over a few hours will probably or get it, but with the cost of these things today, it’s very cheap insurance keeping it maintained! Being stranded sucks!!!

[mikebossy]

dont be afraid to add what kind of motor it is, ie model Optimax? Verado? regular merc four stroke?, when you say 300 hrs for plugs makes me think its one of their fourstrokes

[briangeorge]

You are correct Mike it is the 4 stroke Mercury. I went ahead and replaced the alternator belt. The existing belt looked fine but now I have a spare belt. I also changed the 4 spark plugs. The old ones looked pretty good hey for $5.75 per plug I thought may as well change them out. The only thing left is impeller and I think I will leave that till spring. Didn't think it made much sense to install a new impeller and leave the boat in storage for 5-6 months.
Those 3 things belt, plugs and impeller are what Mercury recommended changing after 3 years or 300 hours. My boat is on season #4 and since I have no idea of how may hours are on it I chose to go with years instead. Thanks to all for the input.

[dodgeboy1979]

You are correct Mike it is the 4 stroke Mercury. I went ahead and replaced the alternator belt. The existing belt looked fine but now I have a spare belt. I also changed the 4 spark plugs. The old ones looked pretty good hey for $5.75 per plug I thought may as well change them out. The only thing left is impeller and I think I will leave that till spring. Didn't think it made much sense to install a new impeller and leave the boat in storage for 5-6 months.
Those 3 things belt, plugs and impeller are what Mercury recommended changing after 3 years or 300 hours. My boat is on season #4 and since I have no idea of how may hours are on it I chose to go with years instead. Thanks to all for the input.

you are lucky, the plugs for my optimax are $20 each (3 plugs), fuel filter is $35 and air filter is $35. lol

[TROLLER]

You are correct Mike it is the 4 stroke Mercury. I went ahead and replaced the alternator belt. The existing belt looked fine but now I have a spare belt. I also changed the 4 spark plugs. The old ones looked pretty good hey for $5.75 per plug I thought may as well change them out. The only thing left is impeller and I think I will leave that till spring. Didn't think it made much sense to install a new impeller and leave the boat in storage for 5-6 months.
Those 3 things belt, plugs and impeller are what Mercury recommended changing after 3 years or 300 hours. My boat is on season #4 and since I have no idea of how may hours are on it I chose to go with years instead. Thanks to all for the input.

Where did you buy the plugs?

[sundancedan]

you are lucky, the plugs for my optimax are $20 each (3 plugs), fuel filter is $35 and air filter is $35. lol


Air filters on an outboard are an interesting subject, theirs not much dust or dirt on the water, besides whats in your cowling, or if squirrels/mice get in.

Most of your Mercruiser products have flame arrestors, rather than a filter... also, 90% of the foam filters on the market can be sumply cleaned with soapy water.

I forgot to add... ALWAYS ALWAYS ALWAYS change your oils.

[SamSteele]

My boat is on season #4 and since I have no idea of how may hours are on it I chose to go with years instead. Thanks to all for the input.


A Merc dealer can plug a scanner into your motor and tell you the hours. You can then install a simple hour meter under the cowling that will track it from there. I picked one up for around $20 if I recall correctly on my last boat.

Or you could install SmartCraft gauges, but that’s quite a bit more money and time. You may be able to buy just the scanner as well, but I haven’t looked into that.

[dodgeboy1979]

Air filters on an outboard are an interesting subject, theirs not much dust or dirt on the water, besides whats in your cowling, or if squirrels/mice get in.

Most of your Mercruiser products have flame arrestors, rather than a filter... also, 90% of the foam filters on the market can be sumply cleaned with soapy water.

I forgot to add... ALWAYS ALWAYS ALWAYS change your oils.

The air filter is for a belt driven air compressor that i believe only the optimax runs. I thought it was strange too.

[briangeorge]

Where did you buy the plugs?

NAPA is where I picked up the plugs TROLLER.