Old merc outboard details?

[Snookie71]

Yes ----I know it is a 4 cylinder motor !

Well a 17 pitch still runs like ****... Will get a 15 this week and try it

 

[Faztbullet]

If thats the boat in the picture a 17P is about correct. Need to check compression and spark first before buying a prop.

 

[Snookie71]

If thats the boat in the picture a 17P is about correct. Need to check compression and spark first before buying a prop.

Compression is sweet... Spark is lekker and no problems...tried a 17 and one person it just gets on the plane... Made a 6 inch jack plate for it and still no luck... The boat has no water in the Hull.. The boat is a 14'4" River Ranger made by Fibre Craft here in Zimbabwe..

 

[Faztbullet]

What is compression? Motor should spin a 17P easy on that hull. Will spark jump a minimum 3/8 gap on open air spark tester( not a neon)? If all checks good you have carb problems

 

[Snookie71]

Spark is good... Compression is good.... I have done the carbs and all good...

 

[racerone]

Boat should fly with that motor.-----Checked the reed valves ?-----Fuel pump diaphragm replaced ?

 

[merc850]

You need a tachometer to establish your rpm such as this one sold on this site
32905 - 4" Tachometer 7000 RPM's for gas Outboard engines.
Perimeter-lighted white dial with bold black graphics black aluminum bezel and flat glass lens. All it has to be is alternator signalled. Sometimes a dealer has NOS ones or "pulls" from a boat.

 

[racerone]

Best to find out what is wrong with the motor first.----Checked flywheel key ( timing ) if equipped with one ?---Fuel pump diaphragm ?------Checked for blockage in exhaust housing ?---Reed valves checked ?----Post actual compression test values.-----Al ignition wires from switch box going to the correct coil ?

 

[Faztbullet]

What is compression numbers.... your good may be bad

 

[jimmbo]

How long have you had this motor? Do you know if the gearcase was ever replaced? If the compression is good, and so is the ignition.... Check the gear ratio. Your engine should have a 2.3:1 ratio. A gear case from an inline six, will bolt up, and has a 2:1 gear ratio, which would make it hard for that engine to spin a 17 unless on a very light boat

 

[Snookie71]

How long have you had this motor? Do you know if the gearcase was ever replaced? If the compression is good, and so is the ignition.... Check the gear ratio. Your engine should have a 2.3:1 ratio. A gear case from an inline six, will bolt up, and has a 2:1 gear ratio, which would make it hard for that engine to spin a 17 unless on a very light boat

Thank you... Right a 80hp Mercury of this age would have a twin cylinder trim... The leg that is on here has a single one like a the newer motors... So I think that's the stuff up... The top is definitely Mercury but the leg and transim bracket is Mariner

 

[jimmbo]

Thank you... Right a 80hp Mercury of this age would have a twin cylinder trim... The leg that is on here has a single one like a the newer motors... So I think that's the stuff up... The top is definitely Mercury but the leg and transim bracket is Mariner

The transom bracket, on your engine is Post 1983, used by both Mercury and Mariner, and uses a Power Trim System that is completely contained within the Bracket, using 2 Short Trim Rams, and 1 Tilt Ram. Looking the Pic, someone retracted Trim rams all the way in. That is done on OMC Outboards, but not on a Merc/Mariner Outboard. Your engine might be a 1984 or newer with a Cowl Wrap, or Cowl Decal from a 1980 - 1983 engine. Of course the outboard could be a collection of many engines, and it is then a Frankenmerc

 

[Snookie71]

How

How long have you had this motor? Do you know if the gearcase was ever replaced? If the compression is good, and so is the ignition.... Check the gear ratio. Your engine should have a 2.3:1 ratio. A gear case from an inline six, will bolt up, and has a 2:1 gear ratio, which would make it hard for that engine to spin a 17 unless on a very light boat

Howzit... Long week of going over it... So I took it out and no change.. So I made a tank on the farm and played... Carbs done timing played with... And to the dam today and still runs like crap... Came back did the carbs again then something said check the trigger wires... One burnt and broken... So I guess I am winning finally... Tomorrow I will make a puller and pull it down and repair the broken wire... Timing light coming Tuesday night...