Old merc 25hp

Don't kill me for posting this as I have given a good shot at searching the forums. New member here, been viewing for a long time. I have an 86 tracker panfish with what I believe is an 84 merc 25 2 stroke. Carbs were professionally cleaned a while back before I got it ( my father in law had it done) but it hasn't run great in a few years. You have to keep the idle cranked up to keep running or she will die. I am assuming the carb needs rebuilt again. I run non ethanol and stabil for storage. My plan is to do the decarb with seafoam spray and run a tank through with seafoam and if it persist to not idle then I will pull the carb. Problem is I can't seem to find a rebuild kit this old outboard- would a newer kit work?

Lastly - I fish mostly around fort bragg NC as well as Jordan lake nc. The bragg lakes limit to 25hp which why we aren't upgrading. Is there a bigger carb that would fit the 25hp block or am I pissing up a rope on this one?
Thankyou much

These are hard to find the kits for. I have to go through the same ordeal everytime I get one of those. They are almost always worth the effort. Find a knowledgeable Merc Parts Man. One of the diagrams shows the number but you have to dig for it. You would think they would revise that.

Also, if frustrated by all other efforts, the crank seals can do exactly what you are describing. They are 30 years old in that motor. They very well could be leaking air into the crankcase at low speeds.

Crank seals sounds very involved. Hope this doesn't go that far! I was kind of thinking the jet or meter for the idle was clogged and furthermore hoping a little seafoam would fix it.

I like Seafoam and use it quite often in my mower/motorcycle/outboard, but it's not a "Mechanic in a can" so it can't fix everything. And unless your problem is caused by a small amount of varnish buildup in a jet, it's probably not going to solve your problem. A good manual carb cleaning can do wonders. If you can't do that for yourself, you might want to learn how to or bite the bullet and take it to a pro. I don't want to steer you away from this board, but this is more about boats than motors and there's just not a lot of Merc guys on here compared to the JohnnyRude drivers. If you don't get the answers your looking for on your parts, you might want to visit the Merc section over at Iboats and ask those guys.
https://forums.iboats.com/mercury-mariner-outboards-25/

Thanks 3micheal - I will definitely become a member over there also. I have seen the site before. I definitely ain't paying for someone else to rebuild the carb but I'm still having trouble finding a rebuild kit.

[url=https://www.tinboats.net/forum/viewtopic.php?p=347070#p347070 said:

86tracker » Today, 11:18[/url]"]Thanks 3micheal - I will definitely become a member over there also. I have seen the site before. I definitely ain't paying for someone else to rebuild the carb but I'm still having trouble finding a rebuild kit.

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If there's a kit available for that carb, some of those guys should be able to point you to it. They very knowledgeable when it comes to a Mercs.

Thankyou. Still waiting in word over there. I have to go find the serial number on the engine to help.

That site seems to be a lot busier with bigger outboards/ have my fault for not updated the serial number yet I'll admit. Here is an update none the less. I seafoam sprayed the carb and she start up first crank with no choke and no pumping and runs like a raped ape but still won't idle without the idle set high. In order to get it in gear I have to drop the and immediately slam the forward throttle to keep it running. When it takes off I can lower the throttle almost to a slow troll but any less and she will stall. Do you think I just need to adjust the idle up a little? No tach on this one and we are not over revving on the muffs - doesn't sound like it anyways.

From all the hoops you have to jump through just to put it in gear or change gears and keep it running, I don't think increasing the idle is the answer to your problems.

I agree with you. I think I'm just going to call this one a work in progress and start slowly working through it little by little throughout the season until I narrow it down and get the idle down. I got a few more good responses on iboat about the carb I will try and I think a ach is probably going to be a must to figure this one out. Thankyou for the help and if there are anymore suggestions I would like to hear them.

What is the model number on the carb? Its stamped in the carb somewhere.

Steve

I will get that and engine serial numbers as soon as I can. Boats at father in laws house and wife wants to get the spring cleaning done this weekend - it's a beautiful day for fishing and I am stuck. Best of luck to y'all on the water this weekend. I'm screwed.

Don't feel too bad about missing out on the fishing. I was out yesterday and at one point my 40# TM set on 5 could not gain ground trying to pull my boat against the wind. The next five days the wind is forecast to be between 9-15 mph every day with 30-60% chances of rain on 3 of the next 5 days. :?

Ha well as they say a bad day of fishing beats a good day of.....