1983 Mariner 115 inline v-6 problems

[illinoisbassfishin]

I am new to this forum and this is my first post. I have an 83 Mariner 115 inline v-6 outboard on my ranger 330v. I recently just bought this boat and got a really good price on it and it is really good shape but I'm having the motor problems.

1st problem is the first time you start it up you can crank and crank and it won't start at all, but if you give it a quick shot of starting flluid it fires right up and once it fires it idles perfectly and sounds really good when it is idling. If you leave the motor shut off and not running for a period of time up to 30 minutes or more it won't start again unless you use the starting fluid then once again it is fine.

2nd problem is whenever you take off on hole shot and you floor the motor it will bog down and die, but if you accelerate really really slow to about half throttle then floor it will take right off and run perfect down the lake at about 45-50 mph. This problems is included when you trailer the boat. When you give it gas to push itself up on the trailer it will bog down and die as well.

I just bought this boat off an old man and you can tell he took really really good care of it. He told me that the last time he ran it was last October and it still had about a half tank of pre mix gas and oil in it that has been sitting since October. We topped the fuel off and added oil and a can of sea foam thinking that would help clean the carbs out and get it back up and going. We have almost ran all of that gas out completely with only about 3 gallons left in the tank and it hasn't came out of it yet. Tomorrow we are going to look into seeing how hard it will be to take the carbs off the motor and clean all of them really good and see if maybe there is a bad diaphragm or a needle or something. Also we changed out all the spark plugs yesterday before we took it out and that didn't help it out at all. Besides cleaning out all of the carbs does anyone else have any advice at all as to what else the problem could be? Any help would be greatly appreciated. Thank you very much.

 

[illinoisbassfishin]

Re: 1983 Mariner 115 inline v-6 problems

sorry but i also forgot to add that there is a small leak in one of the carbs.

 

[Wingedwheel]

Re: 1983 Mariner 115 inline v-6 problems

It sounds like you need to rebuild your carbs. If one of them is leaking that could be a major source of your running issue. Also never use starting fluid to fire up a 2-stroke. There is no lube in the ether and could damage your engine. Always use a squirt bottle with mixed fuel in it.

 

[fishdog4449]

Re: 1983 Mariner 115 inline v-6 problems

If the motors an '83 115hp, it's an inline six. V-6 Mercs are newer than 83 and 150hp and up. The inlines are hard to start when cold, make sure the carbs are clean and choke butterflys are completely closed. Prime the bulb to the point of flooding the carbs, then crank for a few seconds, prime the bulb again, and crank for a few more, holding the choke the whole time.
My 115 was the same way. Make sure to 'tuck' the motor in, tilted all the way down it helps the fuel flow better.
Has the fuel pump been checked or rebuilt? A worn diaphragm would not help the problem.

2nd problem sounds like carbs, make sure during acceleration that the bulb is staying hard, if not it could be the fuel pump.

I would take the carbs off, completely dissassemble, soak in carb cleaner overnight then blow out all passages and jets with compressed air. Rebuild with new gaskets and needles if it needs it. If one carb clogs or runs lean say goodbye to a cylinder or two (know from experience...)

Running seafoam all the time is a good idea. I do one can per 60 gallon tank in my wellcraft.

 

[illinoisbassfishin]

Re: 1983 Mariner 115 inline v-6 problems

no i have not checked the fuel pump yet. I will do that tomorrow also as well. We are going to try and clean out the carbs before we rebuild any of them to see what happens with that because that is the cheaper route to try first. Why would it run so good once you get it going but it won't take off if you try to accelerate really fast. If you accelerate really slow to a certain point then you can floor it the rest of the way and it will take off and run great up and down the lake?

 

[illinoisbassfishin]

Re: 1983 Mariner 115 inline v-6 problems

well we cleaned out all 3 carbs yesterday and took it out to the lake and it still doesn't start very well and it still bogs down when you give it gas on hole shot or when you give it gas to put it up on the trailer. We did notice that if you pump the ball before you go for the hole shot it will still bog down and eventually take off but it won't die anymore everytime. The choke is working because once you get it started and push in on the key to choke it will try to die when you choke it. I am going to get a new fuel pump diaphragm assembly this morning and put that in and see what happens. If the fuel pump diaphragm doesn't help then I am going to buy a new primer bulb and fuel line kit. We are still getting a gas leak from the middle and bottom carb though and we can't figure out why they are leaking. They are leaking from the bottom of the carbs on a brass screw that looks like you could take a straight edge screwdriver and tighten them but they are tight as we can get them and still dripping fuel. From the boats.net diagram of my carbs they are calling these screws on the bottom side of the carb the- screw, plug-main nozzle. We have noticed that there are other screws on the carb that have a red colored sealant over them like maybe someone else before I owned the boat had problems with leaking as well but I can't think of any sealant that I could put on there that would be resistant to fuel that I could put on them where they are leaking to stop the rest of the leaks. Also the back drag vents we noticed have already got bb's in them.

So I am going to do the fuel pump and if that doesn't work I'll buy a new bulb and fuel line and if that doesn't work then I will be completely stumped???

And also does anyone know of any kind of sealant I could use that would resist gas so maybe I could just plug off those small leaks in those screws or does someone else have any ideas?? Any help would be appreciated.

 

[BassnKY]

Re: 1983 Mariner 115 inline v-6 problems

It sounds like the fuel pump is the problem. If after running the bulb is not still pumped up, it is not drawing fuel. Once the RPM's go up, it is pumping faster and able to get fuel.

When you are rebuilding the pump, make sure none of the passages are clogged, possibly with carbon. This restricts the pulses from the crankcase that make the pump work.

Once you rebuild the pump, you might need to make a slight adjust to the carbs. Remember whatever you do to one, do to the others. (ie... 1/4 turn on each) When you start the adjusting, the rule of thumb I use is as follows:
When accelerating:
A. If it hesitates and sputters before accelerating, it is too rich. Adjust screws in.
b. If it sputters and dies, it is too lean. Adjust screws out.

As far as the leak, there should be a washer like gasket between the screw and bowl. To be on the safe side, I would go ahead and rebuild them. Be sure to note the # of turn out each of the adjusting screws are. They should all be the same. This will give you a starting point when you go to start the tuning.

Good luck!!!

 

[illinoisbassfishin]

Re: 1983 Mariner 115 inline v-6 problems

right now all of the adjustment screws are 1 3/4 turns out from lightly seated. Is there any reccomendations that anyone can give me on how they are supposed to be adjusted?

 

[Bob_VT]

Re: 1983 Mariner 115 inline v-6 problems

Take it to a mechanic and get a link and synch operation performed.

 

[illinoisbassfishin]

Re: 1983 Mariner 115 inline v-6 problems

yea the mechanic shop is my last resort if this fuel pump doesn't fix it. My father used to be a mechanic and knows a lot about any carburetor engine so we are hoping we can figure it out so we can save us some money. If this don't fix it we are going to hook up the timing light next weekend and do all that stuff when we are off and we also ordered a manual for the motor to help us out even more. He's picky and being that he used to be a mechanic he believes that a mechanic will try to fix things that don't need to be fixed just to get more money out of your wallet lol.

 

[BassnKY]

Re: 1983 Mariner 115 inline v-6 problems

Good luck!!!
Let us know what happens.

 

[illinoisbassfishin]

Re: 1983 Mariner 115 inline v-6 problems

I will be sure to post back what happens with the fuel pump etc. Hopefully I can get it going and people will be able to use this post in the future to help them also.

 

[illinoisbassfishin]

Re: 1983 Mariner 115 inline v-6 problems

well we rebuilt the fuel pump and changed out the primer bulb and fuel line this morning. I don't know if it helped any on acceleration out on the water because we didn't take it out on the water today, but I do know it didn't help it start any at all. Going to try and fix the gas drips in the carbs tomorrow morning when I get off work and see what that does for us.

 

[Wingedwheel]

Re: 1983 Mariner 115 inline v-6 problems

When you cleaned the carbs did you replace any gaskets? How was the fit on the floats?

 

[Jacket4life]

Re: 1983 Mariner 115 inline v-6 problems

That fuel is probably NOT leaking FROM that screw, more likely is is coming out of the overflow and draining onto that screw. From the description of how you got this motor and the problems you are having, I would STRONGLY reccomend you buy the Mercury service manual for your engine (NOT the Clymer or Seloc) and do a carb rebuild followed by a linc-n-synch. The jets in these carbs are TINY, and it doesn't take a lot to create noticeable problems. The man you bought it from was obviously in the habit of leaving fuel in it all winter every yr, so it proabably has quite a bit of varnish built up. Also, it should cost you $50 or so to rebuild all thee carbs, that doesn't seem like a lot of money to me??

Last thing: be very careful adjusting on the carbs. If you run these motors lean, goodbye piston!

 

[illinoisbassfishin]

Re: 1983 Mariner 115 inline v-6 problems

The fuel is leaking from one of those screws. I took one of the carbs to a marine shop and showed him where we thought it was leaking and he said that was very a common place for them to leak and that's probably why all the other screws like that have been covered up with sealant to keep them from leaking. The carbs have been completely taken off the motor and cleaned and dried out and the carbs looked great and there was no signs of any dirtiness at all which we were very surprised about.

 

[Silvertip]

Re: 1983 Mariner 115 inline v-6 problems

Quote: "It sounds like the fuel pump is the problem. If after running the bulb is not still pumped up, it is not drawing fuel. Once the RPM's go up, it is pumping faster and able to get fuel."

That is not true. After an engine starts the primer bulb will no longer be firm because fuel is being drawn through it. There is no pressure in the fuel line after the engine starts. The primer bulb should not be sucked flat however. If the engine runs fine at wide open throttle you will likely be wasting your money on a fuel line and bulb. If fuel starvation was the problem it wouldn't run well at wide open throttle. You have carburetion or link&sync issues. That requires the service manual for your engine as it simply too long to type here and you need the pictures to guide you.

 

[illinoisbassfishin]

Re: 1983 Mariner 115 inline v-6 problems

well we took all the carbs out and cleaned them thoroughly one day and took it out and it still wouldn't start or take off on hole shot. Next we rebuilt the fuel pump and put a new primer bulb and fuel line on it and still wouldn't start or take off on hole shot. I posted that the carbs were leaking out of some screws on them so I bought some fuel resistant gasket compound and sealed off the leaks completely and let it sit over night. I took it out this morning and it started right up and took off on hole shot and ran like a champ. Surprising something that small is what caused it to not start or take off on hole shot.