1977 1150 I6 questions

[phatmanmike]

hello, motors is 1977 mercury 115hp inline 6.<br /><br />so far i have redone the carbs, fuel pump and water pump. replaced coil, selenoid, wireharness, plugs. <br /><br />motor will now (finally) start, but only with choke 100%closed and if i open the choke, the rpms shoot way up real fast, way to high, so i always cut it off before it implodes. does this motor have idle mix screws, it seems like its getting too much air or to lean fuel...<br /><br />also, water pee hole just dribbles, i have seen it pump after i replaced water pump last month, its pumped since then , but now it just dribbles. water is coming out the prop/exhaust and the motor is not over heating( i can lay my hand on the motor and not over hot.....<br /><br />any ideas on any of this would be great, this is my first merc. i have many other motors but are omc and imports.. so this is all new. i DO have a clymer manual..<br /><br />thanks in advance..<br /><br />m ikey

 

[phatmanmike]

Re: 1977 1150 I6 questions

i found and adjusted the idle mix screws. now it starst INSTANTLY(ive never had one start this easy) revs instantly, great thottle response, and i stuck a short lentgh of wire in the pee hole and now it pees great, musta had some goo in it.<br /><br />ALSO , i decarbed it by taking one can of decarb spray, and squirted some in the carbs and the rest in about a 1/4 gallon of gas... ran it all through, let it sit over night and restarted it in the morning and it is most excellent. all i can say is WOW<br /><br />m ikey<br /><br />ps i hope this can be used for somebody else in the future as what to look for and be used as an education in motors..... thanks to iboats.com

 

[ozarkjeep]

Re: 1977 1150 I6 questions

Hey Mike!<br /><br />congrats on the smooth runnig merc<br /><br />May I ask, how did you acheive a smoth idle?<br /><br />i have a 1970 inline 4 80 HP, the side bowl, back draft carbs, and I cant get this engine to idle unless I advance the distributor quite a bit.<br /><br />also, what technique did you use for setting the idle mixture screws? ( are these the only adjustment on te carb externally?)<br /><br />thanks!

 

[phatmanmike]

Re: 1977 1150 I6 questions

ozark man, hello.<br /> well first let me tell you how big a fan i am of "decarb"ing a motor... its did wonders for me, since motor was so old..... 1976, i know it says 1977 but i was wrong...<br /><br />anywho....<br />idle screws were ALL the way in, and hence the bad running... i turned them all a 1 1/4 turns out from gentle seated... i think i have same carbs as you.. also, take out your back drag jets and throw em away! seriously, these are the jets on the outside of the bowl, towards the top of the carb, i beleive on the left.<br /><br />i changed ALL fuel lines and rebuilt fuel pump! new plugs and make sure they are all sparking. rebuildng the carbs was very easy, about 1 hour.. although it took 3 times that just to get em off the motor and back on. what a pain...!!!<br /><br />any more info, email me<br /><br />m ikey

 

[ozarkjeep]

Re: 1977 1150 I6 questions

Hey Mike!<br /><br />if you dont mind I will ask a xouple of questions here instead of email, that way they can be searched later and might possibly help someone else other than me also! ( I have used the search herefor years to get info)<br /><br />I dont understand what jet you are talking abotu removing? I see the idle jet, and the high speed jet in my manuals diagrams.. but no others?<br /><br />also, I totally dissassembled the carbs and cleaned out everything except the high speed jets a couple of weeks ago, the floats were not set like the book said, they were much flatter ( the bottom "arms")<br /><br />the floats and filters have been replaced at some time as they look like the updated parts in the manual, and the needle/seat assemblies werent pitted or worn, do I really need any hard parts in the carb, or will a simple clean of the jets do?<br /><br />the fuel pump have never been apart, but thru my clear fuel filter I can see a large amount of fuel moving even just at idle, I guess I am going to need a larger tank!<br /><br />I replaced the line from teh tank to teh pump(s) but none of the others, I guess they could be leaking air and I wouldnt be able to see it huh?<br /><br />is there anything wrong with adjusting my idle speed by advancing the distributor a bit? with it moved away from the idle stop screw it will idle smooth and indefinanlty.<br /><br />with it at the screw It wont start or idle.<br /><br />my diel mix screws are 1.5 turns out, I have tried more and less with similar results.<br /><br />also when in gear and driving the boat, from a stand still it will acclerate allright, but it isnt pulling hard past a certain RPM sounds like its surging or starving for fuel, pumping th ebulb doesn NOT help this.<br /><br />I would appreciate any ideas and advice you may have for me!<br /><br />thank you!

 

[phatmanmike]

Re: 1977 1150 I6 questions

is there anything wrong with adjusting my idle speed by advancing the distributor a bit?

yes, . dont do it. your idle timing should be 4 degrees....<br /><br />set the idle speed by the carbs. <br />

I dont understand what jet you are talking abotu removing

these are called the "back drag jets" they are a small brass plug with a hole in it to allow air to get inthe fuel bowl, hence the term back drag<br /><br /><br />

do I really need any hard parts in the carb, or will a simple clean of the jets do?<br />

a simple clean will do. take all plastic parts and filters , o-rings, etc out of the carbs and let them sit in a can of carb /parts celaning solution. available at any auto parts store for 10$<br /><br />

I replaced the line from teh tank to teh pump(s) but none of the others, I guess they could be leaking air and I wouldnt be able to see it huh

yes, mine had small hair line cracks and were sucking in extra air, allowing the motor to run at a higher, yet leaner rpm... and on 2 strokes, lean = bad<br />its cheap insurance, replace em all. i also removed the "plug" at the front of the motor that the fuel lines plugs into, and instead ran a permanant line straight to the fuel pump. one less thing to break and suck air and run lean. once again , lean = bad.<br /><br /><br />

also when in gear and driving the boat, from a stand still it will acclerate allright, but it isnt pulling hard past a certain RPM sounds like its surging or starving for fuel, pumping th ebulb doesn NOT help this

this sounds like a fuel starvation problem. like its not getting enough fuel to run at higher roms properly... check those fuel lines, check the compression, check and clean your carbs.....<br /><br />let us know whats up<br /><br />m ikey

 

[i610288]

Re: 1977 1150 I6 questions

Also check youre fuel pump diaphrams.I had a similiar problem like yours, mine wouldn't low idle only high idle, and wouldn't go to top speed.I checked my diaphrams and they had small cracks in them which made it run to rich.

 

[ozarkjeep]

Re: 1977 1150 I6 questions

thanks Guys!<br /><br />I will get the pump kits on order.<br /><br />compression is 122-123 on all 4 holes, cold, with an old chepa guage that usually reads pretty low, I only use to check consistancy.<br /><br />I have already replaced the fuel fitting with a line all the way to teh tank ( good thinking! haha) and I will replace the other pump to carb hoses also, just in case.

 

[phatmanmike]

Re: 1977 1150 I6 questions

any luck?

 

[ozarkjeep]

Re: 1977 1150 I6 questions

I found the fuel pump kits locally for $7 ( sweet!) I am pick,ing them up and pulling hte boat out of the water this weekend to do the work, every time I try to work on it down at the dock, I drop something important!<br /><br />Did you use the same type fuel lines, or replace with regualr fuel hose and NPT/barbed fittings at each end?<br /><br />hopefulyl I will get a break from lighting the kiddos sparklers to get some work done.<br /><br />I will update when I get it done though.