1977 Mercury 1150 115hp outboard HELP!!!

[johnrondeau]

I was having my brother inlaw write on here before that was a mistake my problem is that i had the motor running without the internal harness when i bought the harness and controls it will not fire and its not getting gas to the spark plugs i brought it to a local merc shop and they told me to invest in a new motor because the cylinder 1 compression was 105 and the other 5 are 125 my manual says try some engine cleaner to clean rings and the manual says 20 psi diferrence indicates scoring i am stuck what should i do

 

[johnrondeau]

Re: 1977 Mercury 1150 115hp outboard HELP!!!

and i took it to the machnic to tell me why it wont start and he did not so waist of 100 dollars i am wiiling to do all the wrenching my self but i am a little green with motors but capable

 

[steelespike]

Re: 1977 Mercury 1150 115hp outboard HELP!!!

Try a decarb treatment with something like seafoam. if its stuck rings compression will go up if other the compression will likely go down.Speaking generically you could remove the exhaust covers and check piston and cylinder through the exhaust ports.I don't know what this involves on an inline merc. The motor will run with poor compression; issue with compression is it can indicate condition problems.Have you checked for spark?Have you tested the fuel pump or carefully primed the carbs with a squirt of fuel or 2 stroke starting fluid?You might contact the guys at Johns Old Mercury web site.The 6 inline is a proven design in production since the late 1950s.The Merc guys will likely say they are wonderful and will know of their quirks.I do know that on some there are timing issues.If indeed the motor needs a rebuild and you have to pay to have it done I think you should move on.Motors after 85 are rated at the prop and will also likely do better on gas.

 

[johnrondeau]

Re: 1977 Mercury 1150 115hp outboard HELP!!!

alright i had it home about three hours reset the timing and it started right up the machanic also said it had low spark it is running good but there is a white milky substance at exaust is this unburned fuel and oil and what should be done next

 

[Gomer50]

Re: 1977 Mercury 1150 115hp outboard HELP!!!

Here is the big question: Is this the kind of Motor that you really want on the back of your boat?Am I willing to invest $$$ to get this Motor back up to its potential??Some people just love the inline 6's and I am now one of them.105 PSI on piston number one would indicate she might have a couple of bad rings and some scoring,maybe got a little to warm due to water pump failure,or bad timing.I did a rebuild on a 78 90hp inline 6 with a bad piston and she now runs sweet.If all your electrical components are still in good shape (because these cost a good chunk of change and are getting harder to find) I would say by all means rebuild her. A good honing new rings maybe a new piston, 3 carb kits, fuel pump kit, engine gasket set and your pretty much back on the water.This is considering all the bearings,reed blocks and a few other things are in good shape. Makes you appreciate your motor alot more too.

 

[Chris1956]

Re: 1977 Mercury 1150 115hp outboard HELP!!!

John, That compression difference is not important. Do a decarb on the motor and forget about it. Make sure the wiring is in good shape or you will short out the ign components. Make sure the gearcase has new clean gear oil.

You are likely seeing 2 cycle oil in the exhaust, but smell it to be sure. Gear oil stinks like rotten eggs, and 2 cycle oil smells like gas or oil. If it is 2 cycle oil it is normal. It is probably time to rebuild the waterpump., before you take it out on the water.

Install new spark plugs and run it a while with fresh 50::1 gas oil mix. Now look at the sprk plugs. If they are white or greenish, you have timing, overheating or carb problems that need to be addressed immediately. If they are brown or black, the motor is running normal

 

[johnrondeau]

Re: 1977 Mercury 1150 115hp outboard HELP!!!

Thanks guys i just put it in the river for a try. ran good no more milk once i change the gas the only thing now is that the control box that i bought used doesn't work wright in foward i think you have to advance it all the way to get up its not gradule i am thinking cables are bad or control box and the motor started cutting out top end so i think i need to work more on the timing or maybe the carbs also when i tilt the motor gas comes out of the carbs the control box is a mercontrol same year the cables are about 1ft to 18in to long

 

[Chris1956]

Re: 1977 Mercury 1150 115hp outboard HELP!!!

Cable length is not an issue as long as they are not kinked. Throttle should start to enagage when throttle handle hits the 1:30- 2 o'clock position. Full throttle is 4 or 5 o'clock.

Hich speed cut out can be fuel restriction or bad fuel pump. Pump primer bulb. If motor stops cuting out, rebuild fuel pump.

 

[johnrondeau]

Re: 1977 Mercury 1150 115hp outboard HELP!!!

this is a old control box with thewarm up lever and a shft/trottle not shore if i have the right cable i am going to find out i took carbs apart today and the top carb float was full of gas so i am going to rebuild the carbs thanks