Mariner 25hp 1987 Handling

[ngentile]

Hello,

I?m new to the outboard motor community. Used to have a Seadoo jetboat? was in the shop more than out to sea.

I now have a Mariner 25hp 1987 on a 14ft aluminum v-hull. Can someone please help me with the following problems:

1.Engine is loud. I hear the air intake along with a lot of noise. I?ve heard other outboards and they weren?t this loud. What is the first thing to do to ?smooth? out the sound and silence it just a little. And BTW it pushes my boat like a bat out of hell! More power than I?d ever need. But what I can I do about the idle noise? (i.e. Clean Carb, Rebuild carb, insulate cover? etc)

2.Idle is rough and konks out if I?m not giving it a little gas. Is there adjustment or do I need to rebuild carb? etc.

3.When I?m out running the engine and I open it up full throttle the tiller pulls hard to one side. Is that wind shear? If not what causes this and how can I fix?

4.Where is the least expensive place to by parts. I?m not one of those guys that thinks he will die if he buys something that is not name brand. So yes? where are the cheap parts. (I?m looking to install an electric starter)

Thanks for any help you can lend my way.

Best,

Nick

 

[verado7]

Re: Mariner 25hp 1987 Handling

if the carb has one of those cages over the front of it -that will soemtimes cause a loud howl - you can remove it - merc outboards are louder than others anyway - then again this might not be related to your problem - its worth a try though .

 

[DADDYRABBIT1]

Re: Mariner 25hp 1987 Handling

1. These motors are a little loud like previously posted, but chech silencer in front of carb for proper fit

2. Get a repair manual and check spec for carb adjustment. I think the correct setting for that motor is to tighten the piolt screw until it just does seat and then back off exactly 1 and 1/2 turns, this controls the air/ fuel misture. Then look for a hole in the front of the silencer that gives you access to the idle adjustment screw and adjust until idle smooths out. You might have to adjust the rod set to make sure the roller is set in the proper position when you have the desired idle. But again consult repair manual for exact info.

3. check and make sure motor is mounted on center. Weight distrubution can also cause pull to one side or the other.

4. iboats sells several aftermarket parts for this motor at fair prices if you are not an OEM part only guy.

 

[will941s]

Re: Mariner 25hp 1987 Handling

The motor is loud and it's going to chop while at idle....all that merc power. I own 2 of them. REALLY fast and bullet proof motor though.

The pulling issue: On the top of the lower unit there is a bolt screwed through the lower to the trim tab. Loosen it and turn that tab the opposite direction of the pull. Do this until the motor tracks straight. Loosen, turn, tighten, try......repeat until it's where you want it.

Loud: With or without the airbox your going to hear the sucking noise. On the water it's going louder then everyone elses 25's. Never heard one that was quiet. They let in alot of air and let out alot of freeflow exhaust. The shortshaft motor is louder than the longshaft.

Idle: Back the motor in the water and leave it attached to the trailer. Get a flat head screw driver, remove the cowel and start the motor. Put it in gear (just in gear, don't give it gas). On the top of the carb there is a screw, thats your idle mixture adjustment, the only one you can adjust. It's set already, well kind of anyway. Adjust that screw while running in gear a fraction of a inch at a time clockwise (lean) until it begins to die. Then adjust it the same way counterclockwise (rich) until it begine to run like crap. Then about a 8th of a inch or so clockwise until it evens out and stays at idle. Put it in neutral and give it a minute for the rpm's to even out. Put it in gear again and see if idles, hit the gas and back to idle. Then to neutral to make sure it idles. If it does then it's good.

Run a water fuel seperator, change the plugs, water pump, and clean the carb once a year. 50:1 oil fuel mixture (I run 40:1) And that motor will give you ALOT of service.

 

[anzomcik]

Re: Mariner 25hp 1987 Handling

For the noise issue, i think you got a motor similar to mine, it has a fiberglass hood? Well mine had not anything in the hood, so i bought some foilcoated foam that had a sticky side and lined the hood with it and it helped out alot, It still is louder than most motors but better, I had like 20$ in that "fix"

I love my 25, she has been a good motor and fast

 

[ngentile]

Re: Mariner 25hp 1987 Handling

Thanks for all the tips...

will941: I tried the idle tweak

Anzomcik: where did you get this foil coated foam you speak of?

Regarding the idleing issues:
What I'm finding is that it idles perfectly in the water when I first launch. Then after I open it up and run it a few times around the lake it starts idleing very rough and will konk out and idle rough for the rest of the day. Why would a warmed up engine start to konk out? Whereas when its cool it itdles fine??

Thanks

 

[zodiacboy337]

Re: Mariner 25hp 1987 Handling

So I also have a Mariner 25hp longshaft. It runs perfect at 1/3 to full throttle. Yesterday It kept dieing at idle. Now it runs very rought at a idle and smells very rich, I took the carb apart and the float seems fine. Any idea's? thank you