Motor Issue, any ideas?

I have a 1995 Mercury 60 hp. Two stroke oil injected. Just got the boat out of storage after almost 2 years. The gas tank was full when stored and had Stabil added. Put it in the river and it started quickly and idled fine. Took off from the boat ramp and it ran fine at low speed. When I tried to accelerate it would bog down and almost stall. Went up and down the river at low speed, but everytime I tried to open it up it would bog down. Any ideas? I assume I should probably start with replacing gas. I thought the primer bulb was acting funny. Anyone think this could be the issue? Thanks for any input.

Drain and go with new gas.
Replace primer bulb and hose (just to make sure there are no cracks, cheap fix just to be sure.)

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Drain and go with new gas.
Replace primer bulb and hose (just to make sure there are no cracks, cheap fix just to be sure.)

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X2

^^SOLID^^

I’d start with new gas also. At the same time, try having someone pump the ball as you’re giving it some throttle (be careful!). If the primer bulb is sucked in at the sides, or the engine revs while pumped, you might have a bad check valve in the primer bulb. Esp. if it’s been in storage with ethanol gas and/or you’ve got the original lines in that boat, this may be the culprit. On my current boat, I had to replace the lines and primer after about 5 years of use. My motor was running full-tilt and then killing for no reason. Replaced the lines, all was well.

Joel

What to do with over 10 gallons of (possible) old gas.

IF it doesn’t smell like varnish, siphon 5 to 10 gallon in your car/truck. Try not to use more then a 1/4 tank of bad gas to good gas.

If it smells like varnish…you’re on your own.

Fuel lines or primer bulb are all great things to try. My boat acted the same way at the start of this year and took it in to find out the carberateurs needed to be cleaned and rebuilt. Fuel line and primer bulb equal cheap fix , carbs not so much!!!! Good luck!

X3 – Sounds like a bad primer bulb.

-J.

That is carbed correct?

Take a look at my post on 25hp honda issues. Sounds be just a few below this. My motor went about two years also in storage. Full take of treated gas and even started it once or twice a year. Where the difference is mine would start but only run on choke or high idle.

Would most likely start with the easy stuff like mentioned above to. New gas, new plugs, new fuel line. If that doesnt do it tear into those crabs.

had the same thing happen to me. it turned out the carbs needed to be cleaned.

Same thing here. Swapped out the line and bulb BUT I also added some Seafoam I really believe that is what fixed the problem

The first time my merc acted like that I learned to loosen the cap on the tank. After 55 years with Evinrudes and Johnsons, it only cost me $30 at the repair shop to find out about mercs.

Restricted fuel flow could be an issue, but my leading suspect would be that fuel and oil deposits are gumming up the high circuit in your carb.

I’d replace the primer bulb, but be prepared for this not to be the issue. Then I’d just keep running it. The fuel flowing through the carb will most likely wash out the oil and deposits.

If it doesn’t improve after a half hour or so of higher speed running time, then I’d tear downt the carb and do a deep creep cleaning of the whole carb including a good overnight marinade of varnish-cutter.

This is one case where adding some carb cleaner to the gas might help, but don’t go nuts with this. A few ounces is plenty and it only works after you run the engine enough to get the carb cleaner up into the actual carb, so either way running it is the essential ingrediant.

Ideally, I would do the test running at home in a test tank. I’m not a fan of running on muffs for extended periods of time. I found a big “utility tub” at menards that’s just about perfect for a test tank. I set it up on a couple of landscape blocks and then tilt the trailer up until the lower unit is under water.

It’s much nicer to run an outboard under water in a test tank where some of the noise is absorbed. Especiallly when you have to run it for an extended period to really try something out.

Grouse

I swear by SEA FOAM, BETTER THEN STABALIZER, DOES MORE, I ALWAYS RUN IT…

also check the pickup tube in the gas tank. The tube may be
going bad. Easy fix

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It’s much nicer to run an outboard under water in a test tank where some of the noise is absorbed.

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I prefer the noise and smoke. Keeps my neighbors on their toes!

Thanks for all your input guys. It is greatly appreciated. I’ll give these ideas a try. Feel free to keep the personal experiences or ideas coming.

I have also had the line in the tank to the strainer crack just enough to allow idling. Took me awhile to find that

An extra tank and hose are two great diagnostic tools. Switching out these items one at a time can quickly help to isolate where the problem is. Air leaks can certainly cause the problem described and having an extra tank and hose allows you to diagnose these problems in just a few minutes and without tearing anything apart.

I had the OP’s exact problem with a 15 HP last spring. I tried the fuel system cleaner route, but still couldn’t get it wind up to full throttle. It would die out.

Finally I bit the bullet and did a full teardown of the carb and an overnight maranade of de-gunker. I had a carb kit bookmarked and ready to buy, but I figured I’d give the cleanout solution a try first. Worked like a charm.

I am NOT a fan of adding detergents to every tankful of fuel. Engines are NOT tested to run on these extreme concentrations of fuel system cleaners so you’re as likely to be damaging your engine as you are to be helping it.

There is an urban legend out there that Seafoam and other fuel system cleaners somehow “cancel out” the effects or negative properties of ethanol. Seafoam is a detergent, it does nothing to alter the properties of ethanol, nor does it “remove” water from fuel. Nothing except a mechanical water seperator can remove water from fuel, there is no chemical that “eats” water and nothing can reverse phase seperation should it occur.

The best preventative medicine for outbords is to use them regularly, keep them tuned up, run fresh, high-quality fuel, and store them properly. The vast majority of outboards die from lack of use and improper storage. The rarest thing is an outboard that is used so much that it wears out.

Grouse

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If that doesnt do it tear into those crabs.

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Mike are you sure you weren’t having a different sort of issue?

Been a lot of years since having those issues.

Well then, just don’t let em’ get around if they come back!