How to change Mariner from starting off on 2 cyl.s

[cootersplace]

As I understand it , this 1993 115 hp. Mariner 4cyl will start off on 2 cyl.s till it hits 1800 rpm and then go to all 4 cyl.s Is there a way to eliminate the starting off on 2 cyl.s ? Thanx for the input . Cooter

 

[Spidybot]

Re: How to change Mariner from starting off on 2 cyl.s

This is handled by a pretty enginious mechanical system, based on pressure in fuelsystem. It is not simple to disconnect, but ofcourse you can run hoses by it and have a constant feed to all four carburettors. I fear it may take some modification to the carbs as well as only the two upper ones are designed to work in idle.<br /><br />BTW: Why would you wanna change it?

 

[cootersplace]

Re: How to change Mariner from starting off on 2 cyl.s

I am not sure why. But I have not run it yet , this motor has been sitting for 4 years and has approx. 75 hours on it , so its like new , but I am doing all this stuff like rebuilds on all carbs and water pump ,fuel lines , trim & tilt ,and now the stator . Any way friends of mine bought it new in 1993 and they parked it when it started not running right . So I thought maybe the reason for not running right could be this 2 cyl. thing . I don't know anything about this 2 cyl. thing . Thanx Cooter

 

[dilligafda]

Re: How to change Mariner from starting off on 2 cyl.s

The operation of the 2+2 system is actually quite simple. The bottom carbs provide only enough fuel for lubrication, but not combustion until 1800-2200RPM. At that point, the throttle butterflys open the passages in the carbs that allow more fuel to flow and allow combustion for operation on 4 cylinders. Modification to idle on 4 cylinders would be difficult considering the engine is designed to idle on 2. Hope this info helps!

 

[dhud64]

Re: How to change Mariner from starting off on 2 cyl.s

I have a 98 model 115 Mariner, i am finding out now that it idles on 2 cylinders. It runs rough on these two cylinders and a carb job didn't help. I wish I had known this before buying it. It's the only thing on the boat I dislike.

 

[cootersplace]

Re: How to change Mariner from starting off on 2 cyl.s

Maybe there is still something wrong with yours , its hard to think that they would put these motors out for that many years if they idle so rough, people would not have kept buying them I would think. Let me know if you find out something about your idling. Thanx Cooter

 

[Spidybot]

Re: How to change Mariner from starting off on 2 cyl.s

My 115 Merc runs like a dream. Idles at < 1000 rpm all day long, never fouls a plug.<br /><br />A slight roughness can be detected the moment it changes to run on all 4, but it is amtter of seconds.<br /><br />I once found it rough running around 1200 rpm, but 4 new plugs solved that right away.<br /><br />This is yet another occasion to mention, that you need a manual if you want to DIY or just to know more.

 

[cootersplace]

Re: How to change Mariner from starting off on 2 cyl.s

What year model is yours . And I wonder if the owners manuel has more info on the running of it, than the repair manuel ? Thanx for your input . Cooter

 

[The Marine Doctor]

Re: How to change Mariner from starting off on 2 cyl.s

If there is a roughness when the change occurs @ the time the 2 other cyl's cut in...get the accel pump looked at.<br /><br />TMD

 

[Spidybot]

Re: How to change Mariner from starting off on 2 cyl.s

Mine is ´91 but the 2+2 system is the same.<br /><br />Got a Seloc and a repair manual and find them both pretty good on the subject. Remember when you tune it, that only the two upper carbs have screws for idle adjustment. As little as 1/8 turn can mean a great difference.<br /><br />I've seen a couple of those motors running rough and too low idle due to too rich mix.

 

[Spidybot]

Re: How to change Mariner from starting off on 2 cyl.s

1.4 gallons of oil in the reservoir

 

[skier]

Re: How to change Mariner from starting off on 2 cyl.s

Getting these motors to run on 4 all the time is really simple. The bottom carbs don't have idle jets, the top 2 do. Just order 2 more top carbs (That have the jets) and replace the bottom carbs with top carbs.<br /><br />Craig

 

[Spidybot]

Re: How to change Mariner from starting off on 2 cyl.s

Yez, rebuilding it to 4 x top carbs would do. I still do not see any reason, though.<br /><br />On mine the 2+2 does xactly what it's meant to: Saves fuel, makes idle-running better. It idles and runs any rpm for any period of time with no problems. You don't notice any vibrating, uneven run or anything. Just smooth.<br /><br />Starts in idle both when cold (squeeze bulb till hard + 3 times, turn (press and hold) key), and warm (just turn key).<br /><br />If you could get yours running up to specs I'm sure you'd forget about converting it.

 

[cootersplace]

Re: How to change Mariner from starting off on 2 cyl.s

Mines not even on a boat yet , its been sitting for 4 years on a pontoon boat ( that I don't want or need ) so I might not can tell any difference between it or some others . I just did not like the sound of the 2 + 2 thing , but I guess if all is right then it will be ok. Thanx for all the input . I hope UU with the other one will get some adjustments to make his right. Cooter