1978 1150 115HP mercury gas leak 1/8 hose

[jimg984]

this is a project motor that I am fixing up to put on another boat......hard starting when cold,,,,,when cranking over several times there is a gas leak on an 1/8 hose,, which comes off a fitting on top of the engine under the flywheel cover,, on the port side just a little to the rear of the flywheel goes down past the fuel pump was unable to trace all the due to darkness... i can see that the rubber hose rotten and open at the top fitting
what is this hose for and why does it leak when cranking over..
why is this motor hard to start,, after 1st start,, starts very as long as warm
rebuilt carbs adjt floats to specs,,
rebuilt fuel pump
all new hose
new impeller

 

[jimg984]

Re: 1978 1150 115HP mercury gas leak 1/8 hose

this is a inline 6 cyl

 

[AMD Rules]

Re: 1978 1150 115HP mercury gas leak 1/8 hose

Transfer line to provide fuel (lubrication) to the main crank bearings. Fix it.

These inlines are notoriously hard to start when cold. Be sure to prime it well until the bulb is firm, then another good pump (they like fuel). Tilt motor all the way down. engage choke and make sure the choke plates are functioning..... lift fast idle lever and it should start ok.

The newer inline motors used an enrichment solenoid instead of a choke plate system, and this essentially drools fuel in to the carbs to help with starting. You coudl consider switching to this arrangement.

 

[jimg984]

Re: 1978 1150 115HP mercury gas leak 1/8 hose

ADM thanks very much for your help on both issuses

both very important espc the 1/8 lub hose

ths again
jimg984 north carolina

 

[jimg984]

Re: 1978 1150 115HP mercury gas leak 1/8 hose

getting much needed rain in north carolina not able to work on motor where does the 1/8 hose attach to at the bottom,,,,,,

had a suggestion to install an OMC primer from later and later motor
dont know what that is and were to get........ for the hard starting

 

[jimg984]

Re: 1978 1150 115HP mercury gas leak 1/8 hose

sorry later and larger motor

 

[Chris1956]

Re: 1978 1150 115HP mercury gas leak 1/8 hose

That 1/8 hose runs from a nipple on the lower crankcase, next to the bottom main bearing up to a nipple next to the top main bearing. Any oil that collects in the bottom of the crankcase is pumped up to lubricate the top main bearing.

 

[SPUNWHEELS]

Re: 1978 1150 115HP mercury gas leak 1/8 hose

These inline engines use check valves to route the remaining oil from the bottom cylinder main bearing to the top bearing for reburning and needed oiling to the top main bearing. The valve might be a check ball type or a duck call rubber type. This is important to maintain this oil line with these checks in good working order. I couldn't find any mechanic in my town that thought this was a required oil line, and nothing to worry about, but my top bearing burnt that next weekend. My top bearing got so hot it burnt through the distributor drive belt.
I imagine if any air gets sucked into that top seal, it cuts the oiling to the top bearing to nill. The crankcase is operating on pressure and vacuum, so it can suck air into there at times, and you need that extra oil to be dependable and help prevent air intrusion.
You should be able to get this rubber valve at your dealer, or you can do like I did, find a 140 hp inline and use those. These are the metal ball type.
Hard starting is what they do, keep a can of starting fluid handy to prevent killing your starter or your battery. I done some creating plumbing and made a tiny manifold to be able to shoot gas into all 3 carbs with my squeeze bulb. Marc

 

[jimg984]

Re: 1978 1150 115HP mercury gas leak 1/8 hose

ths thats the best explantion of the hose i have got... i can see that the hose is crackered near the top fitting, i will run until i replace this hose....
do you think i need to replace the rubber valve [which i dont understand yet]

tell me more about your home made manifold and it works with your primer bulb... i was thinking of doing something like this
no mercury dealers in this rural area

thank you again for your help
jimg984 north carolina

 

[AMD Rules]

Re: 1978 1150 115HP mercury gas leak 1/8 hose

Just a note to add that if you do use 'starting fluid' be sure it provides lubrication and was intended for a 2-stroke outboard motor. Traditional starting fluid contains no lubricants and can harm the motor. Best starting fluid would be a pre-mix of gasoline and twc3 rated oil. Better to find a way to make it easier to start without having to use starting fluid.

 

[crabbie]

Re: 1978 1150 115HP mercury gas leak 1/8 hose

This forum still amazes me. Today I carefully took a nice photo of my '75 1500 to point out the very rubber hose discussed in this thread. "What is the hose for?" would have been the question I would post with the photo.

But then someone beat me to it and asked the same question yesterday! Ah well.

*My* hose was cracked right at the top, but fortunately there was enough slack that I could cut off the offending bit and re-attached it. Not before blowing (no go) and sucking (did go) on it, though. Good thing no gooey oil came up it!

rodney