125 Mariner run on 2 carbs?

[Whitetail204]

I have a 1998 Mariner 125 on a 17' Procraft. Some one told me that the 125 Merc/ Mariners were designed to run on only 2 carbs at slow speeds to reduce fuel consumption. When I lower my motor all the way down and get ready to take off there is a vibration thru the hull of the boat and a hesitation in throttle response when I get on the gas then all of the sudden it kicks in and gets on plane. It runs great otherwise, Top speed so far around 56 MPH. Is this normal ? Thanks.

 

[Mufasa]

Re: 125 Mariner run on 2 carbs?

It is true, they are called 2+2 motors. The idle and slow speed operation is poor. The transition is about 1,800-2,200 rpms. Yours sounds even worse than normal, there may be carb trouble along with the engineering that went into that model.

 

[Whitetail204]

Re: 125 Mariner run on 2 carbs?

Thanks for the response. Is there anyway of identifying these 2+2 motors for my own assurance. What kind of carb trouble might you be refering to. (dirty carbs,ssticky choke etc.) Im fairly new to the boating scene. Like I said when I get on plane it runs sweet at all speed ranges.

 

[bret walters]

Re: 125 Mariner run on 2 carbs?

rest assured it is a 2+2 engine!!!!<br />sync and link and idle mixture are very very very critical on this engine, and engine trim angle greatly effects the mixture also when at idle speed. if mixture is adjusted when engine is trimmed all the way down, it will be lean when engine is tilted up slightly. <br />get a manual and do a proper sync and link, if the engine still bogs and hesitates clean the carbs. ** this is assuming that compression and spark are good.<br /><br />all 4 cyl. mercury engines with 4 carbs. are 2+2 engines and they can not be made to run on all 4 at idle. spark is present at all times. the bottom 2 cylinders have no idle fuel circut in carbs.

 

[Whitetail204]

Re: 125 Mariner run on 2 carbs?

I cant help but notice that both of you guys have "tech" in your screen names. Makes me feel confident in your advice. The motor actually idles OK just causes the vibration. And also when going to get onplane it doesnt feel like its dying ,it just doesnt pick up right away like I have seen on other motors, thats why my concern. Thanks for all your help. I just bought the boat in December and had it out one time this year and really didnt know what to expect. My prviuos boat had a Force so you can probably guess why Im paranoid.HA HA.