1980 115 hp merc

[heyttown]

Please bear with me as this is not my boat but a buddy I am trying to help and the boat is at his place not mine.. Its a 80 or 81 merc motor..He just bought recently and wanted to get it started..I was told the boat was winterized and not used at all in the 2012 season. Fresh gas and oil mix, fresh battery and the motor on muffs on the hose from the house..I was surprised to hear the motor start after 3 or 4 turns of the key and idled well..Problem is and this is my question, does this motor have a tell tale/ water hose that comes off the starboard side of the motor? I found a black hose that looks to be the tell tale the runs from the motor casing up and on top of the motor
(cant follow hose without taking top off) I started the boat, saw no water coming out the tell tale and shut it down..Ran maybe for 20 seconds but didnt want to do damage.After discussing it for a bit and a couple more swigs of beer we decided to start it again, this time my buddy sat by the tell tale with a dab of spit on his finger, and when the motor started and ran it appeared to have a small amount of suction on the tell tale tube..Again shut motor off after another 20 seconds or so..the suction really confused me, although it wasnt very strong suction.

Me personally have never seen a boat motor that didnt squirt water out the side,but figured to check here first. If I am correct im guessing a dry rotted impeller.. but could it be lack of water pressure combined with the low rpm at idle..(boat started without needing to go into a fast idle,I was impressed) would taking it to the ramp 10 miles away and starting it in the water make a difference? I will try and get serial/model numbers later..Boat is 15 miles from me currently. And the suction action confuses me also..
Thanks

 

[jimmbo]

Re: 1980 115 hp merc

I would first run a length of weed eater string/twine up the tell tale to make sure it is not blocked. When the engine is running water will also be discharged from the prop and from the slits above the ventilation plate. Easy to see whenrunning on the muffs. 20 seconds is more than enough to tell if water is fowing
When buying a used engine it is always good practice to replace the impeller and wear surfaces of the waterpump.

 

[mr 88]

Re: 1980 115 hp merc

In most cases it takes 10-20 seconds at a high idle to get water out the tell tale.If a low idle it may take even longer. As JBO mentioned replace the impeller so you have a fresh start with the cooling system.It takes a lot longer than a 60 seconds to get the head hot at high idle so do not worry about overheating it,you should be able to put your hand on the head and feel how warm it is without burning yourself. The tell tale would have outgoing pressure,not vacuum so if anything you should of felt a bit of exhaust.Do your self a favor and stay away from the brews when fiddling with these. Save them for when it is running with NO problems................

 

[heyttown]

Re: 1980 115 hp merc

I appreciate the responses, and will relay the info to the owner..he may start it and let it run longer after he tries to make sure line is unplugged..I understand it should have outgoing pressure, but when the finger was put near the tell tale it indeed pull the the little puddle of spit on his finger which is opposite it should be..that in itself confused me big time.