1978 Mercury 80 hp outboard trolling speed

[Geno_Vino]

Hello all, this is my first post and I'm new to the boating world. I looked but did not find my answer, so the question is:

I have a 1978 Mercury 80 hp outboard. It runs great at all speeds and starts right up. The problem is at a very slow trolling speed the motor will bog down and cut off after I troll for about 5 minutes. If I catch it before it dies I can idle it up to full and it will take about 2 minutes then rpm's will go all the way up and I can troll again. Spark plugs? Idle speed? Not sure what to do.

 

[matt9923]

Re: 1978 Mercury 80 hp outboard trolling speed

First off welcome to Iboats.

I think you should turn up your idle screw a little bit. This will most likely fix it but it probably needs a tune up. New plugs, carb's rebuilt points rest or new (think it has points). Not to worry you but this is general maintenance to older motors. But i think you will be fine with turning up teh screw a 1/8 turn or so. Not to much but you will feel it make sure its warmed up before adjusting.
Matt

 

[OldMercsRule]

Re: 1978 Mercury 80 hp outboard trolling speed

No points it has an adi system.

It may need a tune up as the reply states but the inlines are not the best for trolling.

Why don't you get a small kicker to troll with? JR

 

[Geno_Vino]

Re: 1978 Mercury 80 hp outboard trolling speed

Yeah I thought about a smaller motor but money! Oh well, I have to make the best...maybe a trolling plate?

 

[OldMercsRule]

Re: 1978 Mercury 80 hp outboard trolling speed

A trolling plate will cost ya money too and I doubt it will make an engine not designed to troll: troll very well.

What ever floats that boat of yers. JR

 

[matt9923]

Re: 1978 Mercury 80 hp outboard trolling speed

You could get a electric trolling motor off fleabay for like $40. And its quiet you can use 1 battery but you will want to bring a jumper box with you or get 2 batteries. 1 starting batt one and the trolling one needs a deep cycle for $60-80.
Matt

 

[rightcoastrob]

Re: 1978 Mercury 80 hp outboard trolling speed

I troll with my merc inline 115 for 12 hrs a day with no problems.I used to have issues when i tryed to use cheap 2 stroke oil,and junk B/P gas i trolled all summer on the same plugs NGK not Champs.And as farr as trolling plates go they work ok they scrub alot of speed in my case i have twin 115s and the both of those plates cost me bout 8 to 10 mph and suck alot more fuel.I plan on selling mine and going with proTroller trim tabs.

 

[Geno_Vino]

Re: 1978 Mercury 80 hp outboard trolling speed

Ok cool I will try to change the spark plugs first. I have the flat kind that are Champion in it now.

 

[OldMercsRule]

Re: 1978 Mercury 80 hp outboard trolling speed

A duck could prolly swim jus fine with a rudder, but it surely would not fly as well with one.

If you wanna do a lot of werk on yer inline, (because ya jus' like too), jus' idle it all day long if ya want to and see where it get's ya.

The inline 4(s) and inline 6(s) were not designed to idle all day long without cornsequesnses, I have run them fer over 40 years and am speaking from me own experience.

If the feller trollin' with the 115, (assumin' it is an inline 6), were to run it properly it would last much MUCH longer with far less maintenence then it will as a trolling engine. Sorry but that is a plain fact, and facts really do matter.

Small engines are designed to idle all day long without cornsequenses, and you can find them at reasonable prices, or you can go with an electric motor as was suggested.

Pay now or pay much more, (time money and frustration), later.

So again I say: what ever floats that boat of yers: GO FOR IT!

Me over priced $.02 JR

 

[Starppy]

Re: 1978 Mercury 80 hp outboard trolling speed

I know alot about the old Mercs too and idling them is just fine. You aren't wearing them out, you aren't beating them up trolling speed idle is fine.

What you have to be careful of on the inlines is that you have a good water pump. YOu have to make absolutely sure that you get good water flow all the way up to the top cylinder.

 

[Geno_Vino]

Re: 1978 Mercury 80 hp outboard trolling speed

Hey Starppy, I've got good water flow of course less stream at low rpms but it's still pretty good. I'm thinking of adjusting my air and gas, new spark plugs and pumping the bulb to make sure there is no air in the gas line. Anything else?

 

[jimg984]

Re: 1978 Mercury 80 hp outboard trolling speed

can tilt motor to create prop slip,,,,,,, make sure to keep water intakes in the water