1986 Mariner 3697- first spring launch/splash

[MrMojoRisin]

Hello,

i've posted a few times this past fall about us purchasing an '86 Mariner 36'. Not sure if this is the correct thread for this post, but here goes anyway.

We have been collecting parts and maintanance items to do do several projects this spring once we remove our shrink wrap and before we launch, and some other projects we'll do once we're in the water. This will be our first spring launch. We have had boats for many years, but always owned trailerable boats with outboards. This is our first with a boat this size and with inboards. The boat is in a marina in Erie, PA and our intention is to launch and stay there for a few weeks before we head west to our home port of Huron, OH.

All our friends with larger boats, are docked at a full service marina where the staff/mechanics do all the prep work and launch the boat and take it to their dock. The marina we are at will launch the boat, and take to my dock, but have no mechanics on staff, so I have to have it ready to roll when they are ready to launch. I'm working on a checklist to start working on so I do what needs done, in order, to be sure i'm ready. Any suggestions for a newbie when it comes to getting ready to launch?

Thanks,

[waybomb]

Do the sea cocks all operate freely?
All the fluids full?
Once it's splashed, check all through hulls and packings for leakage.
Keep some tapered plugs on hand in case a through hull fails.
Start the engines and make sure you have water flow or the exhaust. Same with genset. You may have to burp the strainers.

[Viper]

I echo Fred's suggestions above. You may also want to ensure your batteries are fully charged ahead of time, check their fluids and test them.

Of course check all the fluids as mentioned and regular maintenance items such as belts. Eventually you'll want to replace all fluids and filters so you know when they were last done and can build a maintenance schedule from there. Change the water pump impellers too, and consider ignition tune-ups.

I'm thinking you might have Walter V-drives that are separate from the engines, if so, check their oil levels as well.

Did the previous owner use the boat often? Would it have old fuel or relatively new?

What engine package do you have; Merc, Crusader?

[bud37]

Be sure to explain to them this is a first for you. They should be fine with that and maybe offer some assistance. Go there and watch other launches to become familiar with the process for different boats etc.

If the boat is launched with a travel lift ask to leave it in the slings to do your checks , that way if there is some issue it can be just lifted out right away. Same idea with if they have hydraulic trailer.

Good luck with your new boat. Oh and remember the stress at the ramp as to who did or didn't put the plug in....dear did you put the plug in ?, no I thought you did.....

[km1125]

When were the raw water impellers last KNOWN to be replaced??

If YOU didn't do it, then you might seriously consider doing them before launch. Even if the prior owner said they were done "recently". They are the most-frequent cause of ruined weekends That applies to the genset impeller too.

When you're checking the batteries, also look critically at their connections to make sure there's no corrosion to be dealt with.

[MrMojoRisin]

great advice so far guys... keep it coming.

I pulled all the batteries last fall and took home to keep on tender.. will install fully charged.

So far here is the items i have on the list before launch (have all these parts in my possesion already)
1- replace steering cylinder and bleed system
2- replace belts (engines & genset)
3- replace fuel filters (engines and genset)
4- replace impellers (engines and genset)
5- inspect & clean points, check springs & weights (have pertronix ignitors & coils ready to install)
6- replace spark plugs & wire set (engines)
7- Check Fluids- engines, genset, trans/V-drives
8- Check bilge pumps for operation
9- check sea cocks for operation
10- mount transducer for new Garmin

O yeah, and put in plug.

Once we're in...
change oil & filters (engines & genset)

[MrMojoRisin]

Source of the post
Did the previous owner use the boat often? Would it have old fuel or relatively new?

What engine package do you have; Merc, Crusader?

the previous owner purchased the boat off the original owners estate at the begining of the season in 2025, so only had in his possession for 4 months or so. He didn't strike me as the type that was rigorous with maintanance though. Based on his social media posts, he appears to have used the boat often this past summer. Confirmed that it wasn't just a floating condo with a neighoring slip holder, so i'm guessing the fuel is newer. He did say the fuel gauge wasn't working, i havnen't confirmed it yet, but one of the spade conectors was barely attached at the sending unit, so I'm guessing that was the problem.

I do have access to a guy that knewp the boat and origninal owner well. Said the old man was pretty good at maintanance but things were getting overlooked last couple of years as he aged. He did tell me that the port engine was a new long block with less than 12 hours on it, but with no paperwork available to prove it, I'm not banking that is the case. The hour meter's show 1096 hours port and 1103 hours starboard. Just thinking if your going to the expense of a new long block, why not swap out the hour meter? Of course why put all the old components (starter/alternator/etc) back on as well. Easy to say when it's not your money i guess.

For engines it has the twin Model 350 Crusaders (454's) and yes, does have Walter V-drives. I paid a local mechanic to winterize it last fall, so i haven't spent as much time combing over things as i'd like. Hopefully remedy that in the next few weeks. With a 2+ hour drive to the marina, I need to start making the trips up more productive.

[Viper]

Look for the U cooler at the front of each engine. Pull the large bronze plug on the side at the bottom and see if the anode is still present. It should be attached to the plug.

[MrMojoRisin]

Source of the post Look for the U cooler at the front of each engine. Pull the large bronze plug on the side at the bottom and see if the anode is still present. It should be attached to the plug.

I've been trying to buy up all the maintance items this offseason here and there so i didn't have one big shopping trip at the start of the season. One thing I haven't looked into yet are the annodes. From what i know now, they have them in that U-cooler thing and also in the heat exchanger. Any other's that I should be aware of?

[Viper]

Not as far as the engines are concerned. You may have in the generator if applicable, the hot water tank may have as well but not critical must items before launch. BTW, if the engine U cooler anodes are missing, broken/crumbly, etc. I recommend you back flush the raw water circuit. I suspect the anodes were probably zinc and given that you're in fresh water, the zinc takes forever to dissolve. Any pieces that have broken off the anode might be trapped in the cooling circuit and causing a restriction which leads to sub-par engine cooling, pretty common issue on these. Try sourcing magnesium anodes for the engines.

You'll also want to check your external anodes prior to launch. For fresh water, they need to be either magnesium or aluminum. I only use aluminum for fresh water inboards now.