Mercury 2.5L 200

[Jeremy Sharp]

I have bought a boat with a 1995 200 that the person I bought it from said there had been "work done" but it was before he bought it and couldn't give me any info about said "work". I know there has been some deleted components. I want to continue running this engine but WOT is on hitting 5100. Also stutters at WOT like it is starving for fuel. Had a shop check everything out and they did a terrible job, only rebuilt carbs and made it worse than it was. I'm now losing prime quickly after sitting. I've had to reset floats and am awaiting on fuel pump kit for that rebuild. I bought the boat for the boat not the engine and will repower if I need to, but this thing seems super strong, and I love the 2.5 just don't have enough knowledge. I guess that is just a long way of asking if anyone on the forum with knowledge is close to North Alabama that would be willing to look at it and give me a direction?

[rock]

Welcome to the site. 2.5 200 is a great engine but WOT at 5100 is an issue. What boat and prop?

Rock

[Jeremy Sharp]

1991 Champion 190, 3.5ish POP, 25 Temptest all ports open.

[aj06bolt12r]

Bucks Marine Services in Guntersville. 573 Meltonsville Rd, Guntersville, AL 35976 (251) 406-7369

He's an experienced guy, knows what he's doing.

Could be anything from fuel pickup in tank to collapsing fuel lines to the pulse pump to internal carb issues. But don't keep running it. If its leaning out your gonna melt a piston.

[Jeremy Sharp]

Yeah, I've spoken with him. Hate for my boat to be sit outside for 3-4 weeks. I just thought someone might know a shade tree guy that really knows his stuff that might want to make a few bucks. There were some guys in Southern Tennessee around Soddy Daisy that use to build some boats. I'm sure there is someone here at home that does I just haven't found them yet.

[LakeFever]

Good mechanics are hard to come by and this is also why they are busy. The nuts and bolts of it this motor needs to be “gone through” which takes a bit of time and not a lot of parts cost. First a compression test. If good then All rubber lines should be replaced. Carbs cleaned and reset to spec. Fuel pump service/clean. fresh plugs and any other obvious stuff the tech will see once getting into it. Again most of this cost is labor very low on parts but it can take a while.

To step a little further which I was advised and ignored on my first one of these is to delete all the black boxes and eliminate the oil injection by switching to premix and installing an oil injection delete kit. Again not spendy on parts but well worth doing. Once on premix if the compression is good the thing will rock probably for a long time too. Seeing as I thought my motor ran great why bother deleting? Well guess what happened? Kaboom. Oil injection failure. Ufff

Beware of ethanol laced fuels those attack rubber lines and can cause other corrosive problems to these old motors that were not built with systems to handle ethanol. It’s not terrible to run it, it’s brutal to leave it parked with ethanol in the fuel bowls and lines. But if possible avoid it altogether and this improves your outlook on reliability.

[Jeremy Sharp]

Thank you both. They are so hard to come by. The good, trusted shops here don't really want to work on it once they see it. They have deleted things that I don't even know what all is gone. From cooling system to lower unit. The lower unit has been swapped out and has a low water pick up, but I don't know what lower unit it is. Compression on all is 120-125 range, oil injection has been deleted, premix somewhere between 40/1 and 50/1, no black boxes, all gas and vacuum lines replaced. The only electrical things under the cowl is regulators and powerpacks, and of course stator. The shop I carried it too was for carb build and set. They said the carbs were good, but they were far from good. Carb #1 & 2 needed floats set and carb #3 had the needle laying in the bowl. They also ruined a prop. It never lost prime before they "built" the carbs but now it losses prime and seems to be starving for fuel. I had to link and sync, so just donated them a wad of money for nothing, it ran better before they worked on it, so you see why I'm a little hesitant. I've got a pump kit ordered, and I've set carbs to specs. I haven't torn into the "newly built" carbs besides setting the floats and replacing the needle. Everything I've tested has tested good except regulator and 2 bad plug wires, which I've replaced, and was probably the hiccup all along. Replaced both regulators. I feel like this engine was built to run but it's going to get above my knowledge very quick and was just hoping someone knew someone. Really, I just needed to vent.

[LakeFever]

I hear ya. It sounds like the fuel side of things has been looked over and you’re going to do the pump. The pick up tube in the tank should be checked also if you didn’t mention that. I think a reed valve inspection is worthwhile at this point. You can probably shine a light down the intake throats and see if any have tossed a chunk. If they are stock steel I doubt it because you’d have some other issues. I’d also test the stator for health. The ohm test is quick and easy. Do you have a manual?

[Jeremy Sharp]

Waiting on it to be delivered.

[Jeremy Sharp]

While working on the fuel pump area I found a tiny leak at the crank halves. I’m sure that’s a total tear down. If that’s the case what else would be a must replace while it’s broken down that far? Give me some ideas.

[LakeFever]

Fresh reeds and lap the cages true is always a good move imo. All new gaskets and seals. Add coolant diverters. If you’re going to pull the rods and pistons out metal cage rod bearings are a common suggestion. New rod bolts RB8000 from promarine are the ones most of us use. Make sure you resurface the rod journals before assembly. You can do some porting while in there for a few ponies if you like. Best mod is to increase compression. Most of us run 130-145 psi for these builds on pump gas. Compression makes a big improvement in acceleration.

[Merc 2.5]

Thank you both. They are so hard to come by. The good, trusted shops here don't really want to work on it once they see it. They have deleted things that I don't even know what all is gone. From cooling system to lower unit. The lower unit has been swapped out and has a low water pick up, but I don't know what lower unit it is. Compression on all is 120-125 range, oil injection has been deleted, premix somewhere between 40/1 and 50/1, no black boxes, all gas and vacuum lines replaced. The only electrical things under the cowl is regulators and powerpacks, and of course stator. The shop I carried it too was for carb build and set. They said the carbs were good, but they were far from good. Carb #1 & 2 needed floats set and carb #3 had the needle laying in the bowl. They also ruined a prop. It never lost prime before they "built" the carbs but now it losses prime and seems to be starving for fuel. I had to link and sync, so just donated them a wad of money for nothing, it ran better before they worked on it, so you see why I'm a little hesitant. I've got a pump kit ordered, and I've set carbs to specs. I haven't torn into the "newly built" carbs besides setting the floats and replacing the needle. Everything I've tested has tested good except regulator and 2 bad plug wires, which I've replaced, and was probably the hiccup all along. Replaced both regulators. I feel like this engine was built to run but it's going to get above my knowledge very quick and was just hoping someone knew someone. Really, I just needed to vent.

Im in middle tn and strictly work on these old mercs , feel free pm me if interested. Im about hr and half maybe 2 from north Alabama

[DeuceInNa1/2]

I know Robert personally & often fish on the big G. You cannot go wrong taking your rig to him. Seriously, this dude is an encyclopedia of knowledge on these Mercs. I also own a Splashed Champ Hull (RayCraft 186). I'd highly encourage you to work with Robert.