Need help new owner of a 87 Merc!

[gpatton]

Well so just a couple weeks ago I bought a used boat. It's a nice boat and it came with a 60hp 87 Merc. He ran it for me with the ear muffs and she seemed to run well the day I bought her. Then I took her out for the first time about a week ago. After going threw learning the proper starting procedures I got her started. We idled around some for a few minutes and then decided to get the boat on plane for the first time. She got on plane in just a few seconds and everything was great. Then the engine bogged down and was acting like it was getting any fuel. Well we checked the tank and it has two tanks and the one it was hooked to was out of gas. So we switched to the other and the problem continued. So we got fresh gas and still the problem continued. The air in tank valve was open and the bulb appears to be good at least it is in my dads opinion.

So then today I bought a can of seafoam to try and clean her out some. Before we left we noticed there was a small amount of black oil coming from the prop. We went out and ran it with some of the sea foam and it seemed to help with he idle but hasn't helped with the high rpm problems at all. It just wants to sputter and act like it's gas starved. Then we got back home and a generous amount of brown oil came out of the prop when we lowered it to the normal straight up and down. My dad believes it's a bad seal and water is entering the the lower unit. I've read some articles and posts that suggest this is probably the case. I however also wondered if this couldn't be extra gunk the seafoam is getting rid of. ANy suggestions or tips would be GREAT on the subjects. I'm hoping to avoid a expensive repair bill but that seems likely now.

 

[crem1]

Re: Need help new owner of a 87 Merc!

Sea foam will go through the fuel system but not through the prop shaft

 

[DuckOfDeath]

Re: Need help new owner of a 87 Merc!

If its black it's probably not gear lube from your lower unit. Drain a little bit out of your lower unit and check its color. It's normal to have black exhaust residue drain out the thru-hub exhaust. I see it a lot after running at idle for extended periods.

You may be due for a carb overhaul but I would verify you have spark on all cylinders when it's acting up and also do a compression check.

 

[gpatton]

Re: Need help new owner of a 87 Merc!

Thanks guys I explained the whole story to a couple different mechanics today and they both said it's residual exhaust. ONe said he can do a once over on the motor for a hundred bucks. Then if I'm looking at carb work it's going to be 300$. I'm thinking about runing some more seafoam a couple times to see if that doesn't clean it out first. I'd hate to pay a guy 300$ for something that seafoam might be able to take care of. Then if it doesn't clean it out take her in. What do u guys think?

 

[DuckOfDeath]

Re: Need help new owner of a 87 Merc!

I'm cheap, so I would compare the $100 the mechanic wanted to go over the motor with the cost of a service manual, compression tester and spark tester. You can probably get all of those plus the carb rebuild kits for nearly $100. That's how I justify buying new or specialty tools. I compare what I'll save doing doing the job myself, factoring in the cost of acquiring tools I'll own for life. Carb overhaul is easy. The link and sync procedure that will be required afterwards is easy for anyone that can follow the step by step instructions found in the service manual.

If your compression and spark is good it's time to suspect the fuel system. In that case, you may get lucky with Seafoam in lieu of a proper carb/fule pump overhaul. Good luck!

 

[j_martin]

Re: Need help new owner of a 87 Merc!

Run it a little more, put some seafoam through it, push it all you can, then the lean condition will burn the top out of a piston and you can look at a 2000 dollar engine overhaul.

When you ran the tank out of gas, you pulled the last bit of old crap in the tank into your fuel system. If you're lucky, there's a fuel filter that caught it and is now plugged up. If not, it's in the carbs, and the only way to get them right is to take them off and overhaul them.

It's an easy shade tree project, just takes a little commitment to get the manual and do it right. Ordinary hand tools are all that's needed.

If the hoses are old, they are all suspect as well.

A two cycle engine has about half as many parts in it as a 4 cycle of the same vintage. The design is rocket science, but maintenance is pretty easy.

Being serious now, don't push it. If you do something and try it out, and it balks, back out immediately before you do any damage.

hope it helps
John

 

[gpatton]

Re: Need help new owner of a 87 Merc!

While I was at work my pops picked up a fuel filter for it. So tomorrow we'll install it and float it and run it to see how she does. We are by no means pushing the motor were just trying to diagnose the problem and fix it. I'm new to the larger motors and my dad is a bit new to it as well. So we are asking questions, learning and trying to fix the problem ourselves if we can, but if we can't we'll take her in. Service manual ect are all on our list of things to get.

 

[j_martin]

Re: Need help new owner of a 87 Merc!

Sorry for the macabre humor. Point is that some new owners of these great (in many ways) old engines will inherit them with a fuel fault, and burn them down playing around, not realizing that at WOT there's such a hellacious fire going on in them that a few seconds of overheat (running lean) can permanently wreck things. Looks like you're aware of that now.

I bought a boat with a V6, old and wrong fuel lines, bad fuel pump, carbs out of adjustment, wrong (plastic aftermarket) fuel connectors, and a contaminated fuel tank. It balked a bit at WOT. Had I run it like that I would have burned it down.

I snuck up on all the problems, and got them fixed one by one. Took me a couple of weeks, but man does this thing run nice now.

BTW, the stock thumb sized Mercury filter kept plugging up. I ripped it off and with a flick of the wrist put it in file 13, then installed a 60 GPH filter/water separator.

hope it helps
John