1981 Mariner 150

[brents]

I am looking at a 1981 Mariner 150 thats mounted on a skeeter bass boat. I have a few questions regarding this motor. I have never owned a Merc/Mariner, only JohnnyRudes. Is this a good year for Mariner motors? Is this an electric shift (I hope not)? Are there any common/persistant problems with this motor?

Are parts still readilly available? I saw on Mercs website were they stopped listing parts past the mid 80's.

The motor has had lite use over its lifespan. I plan on compression checks, etc when I go look at it on Friday. What compression range should I expect. Are these lower compression blocks, or do they run higher compression. I know that a variance greater than + -10% would not be acceptable. This motor has never been rebuilt, nor has the leg been rebuilt. However, yearly maintenance (when used) and yearly winterizing has been completed.

Finally, I know with Johnny/Rudes powerpacks/coils tend to not age well. What electrical expectations should I have from this motor. It is currently in good running condition topping 60 MPH with a 23P tempest pro prop.

Thanks for all your help. Any and all information is greatly appreciated as I am not familiar with Merc/Mariner and to be honest, a little scared of this motor since it has never had any major work done. Most motors (in my experience) this age or older have been rebuilt.

 

[brents]

Re: 1981 Mariner 150

OK, so even more research has enlightened me.Since it seems nobody here knows anything about this motor I will share my information. I am hoping someone can chime in and validate for me.

It appears much is shared from 1979-1986 with Merc/Mariner 150's. As I understand the leg is shared through I think 1991. Additionally, parts are availalble new through sources such as Max Rules, and local Merc dealers.

These were not low compression blocks, I should expect compression as high as probably 120ish.

Also, it is not an electric shift and electronics are electronics. They are expensive and have to be dealt with.

I don't think there is any reason I should be scared of this purchase as long as the motor checks out. These 150's from what I can tell are some very good motors.

 

[duckboy007]

Re: 1981 Mariner 150

That's good to hear, I just bought a 1981 Mercury 150 on an old 18' ski boat with a trailer for $200. What is a decent resale value that you have seen? I originally was going to throw it on the back of a bass boat that had a busted motor, but that deal fell through, and I might be getting a boat that doesn't have any issues. We'll see. Good luck with the skeeter, I'm really trying to find something in that under $2000 range that I can get out there and fish with.

 

[Jeff_G]

Re: 1981 Mariner 150

Yes they are good engines. The main problem with the ignition system is bad grounds causing other failures and stators going bad.
An engine of that age I would have the lower unit seals replaced.
Operate the engine normally otherwise. Use Mercury's Hi Performance gear lube. I also like Mercury's Premium Plus oil.
Change out or get rid of the oil injection. The block off plate is under $10.
99.9% of the parts are available from Mercury or through aftermarket.
One thing to watch is corrosion in the exhaust chest on the early engines. If you want pull the rear exhaust cover and check also pull and replace the head gaskets.
I would also recommend doing a water pump kit and new thermostats, rebuild the fuel pump and change the fuel lines to an alcohol resistant hose.

 

[brents]

Re: 1981 Mariner 150

Thanks for the info Jeff. I was horrified at first consideration of this motor. After much research I am feeling more comfortable with it.

If I get it I will pull the rear exhaust cover and check it out. The motor has had off/on use over its life span. So corrosion is definitely a possiblity with as much off time the motor has seen.

I plan to drop the oil injection all together, thats way to much mechanical trust for me. I prefer to pre-mix myself.

Duckboy, good luck with your hunt. I am getting into this skeeter for well under 2K!! Good ole boy deal I would imagine a good running/fresh merc 2.0 could fetch up to 1k, prob sell all day for 6-800. However, I am no pro so don't quote me as other factors play largely in resale.

 

[brents]

Re: 1981 Mariner 150

I also have one other question. I read that any TCW3 oil will work. I have a lot of JohnnyRude TCW3 oil already in my garage. Can I continue to use that with the Mariner, or do I need to buy Merc stuff?

 

[j_martin]

Re: 1981 Mariner 150

I also have one other question. I read that any TCW3 oil will work. I have a lot of JohnnyRude TCW3 oil already in my garage. Can I continue to use that with the Mariner, or do I need to buy Merc stuff?

sssshhhh, it'll work.

duckin' and weavin'
John

 

[Jeff_G]

Re: 1981 Mariner 150

I AGREE WITH JOHN!!!
Yes I'm shouting, John I'll take your back any time. Hide behind me

 

[brents]

Re: 1981 Mariner 150

Thanks guys, I thought it would.

I talked with the owner again and he lent me some more information.

He told me that the LU needs a new o-ring in the fill screw. He said he put some silicone on the screw, and it hasn't gotten water in again. I will replace the fluid and reseal the LU including the the o-rings. I will do some serious looking at this to make sure no silicone could have gotten into the LU. If any got it, could silicone hurt the gears, or would they grind through it? If I don't have to open the leg up completely I don't want to open it completely.

Other than his bad fix on the LU it sounds like he took good care otherwise. I can't wait to see it, I hope its as good as it sounds.

I am confused, I have been consumed with JohnnyRude bias for a few years now. However, now that I am looking into a Merc it seems like they are a lot better than I thought. Parts might be little higher, but the interchangeability is phenominal.

 

[Chris1956]

Re: 1981 Mariner 150

It is doubtful the silicone caused any issue. Use the gaskets, when you refill the gearcase. On that old of a motor, any marine gear oil for mechanical shift motors is good. I only use the synthetic stuff on the mid-90s and newer motors.


In the sixties, Mercs were all inline motors, and 'rudes had small inline motors and the rest were V4, and then V6 motors. Now both companies have copied the best features from each other. They both only make 60* V engines for their larger motors, and inline 2-4 cylinders motors for the smaller HP. The only difference is that Johnnyrudes seem to have a large amount of linkage between the throttle and shift cables and the carbs and triggers. This seems to be a holdover from their first V4 motor (1958 Fat-Fifty), which I thought was the king of linkage, until I got my '98 Johnny 150HPV6, which has more linkage. The mercs have minimal linkage.

 

[brents]

Re: 1981 Mariner 150

OK guys, went and saw the motor tonight. Left bank had 105,110,105, right had 95,95,95. Exhaust gasket was blown, barely any water through the tale tell because of this, and temp sending wire was fried. Also, some other wires looked kind of rough. All this said, the motor didn't appear to have more than 50hrs on it. Heads and block did not have the slightest indication of ever having a overheating problem. Fluid in LU looked great, no metal at all.

The boat was fabulous, decks and floor were solid. Boat had none of the usual chips and dings one would expect with a 1981 bass boat. Of course the gel coat was a bit faded. Live wells all worked, tons of storage. A+ on the boat.

Without rebuilding the block, I am estimating 700-800 dollars worth of work to get it back in shape, myself turning the wrench, mostly electronics. If I could get him to knock this off the price would it be worth my while to still purchase the boat/motor.

Or am I fooling myself thinking this motor doesn't need rebuilt?