1999 Mercury 125 hp outboard Lost power durning high speed

[Superboild82]

Today the family and me took the boat out on a bigger lake the normal. We were running around 35 mph for a 4 miles at 3/4 or better throttle. Then all a sudden I lost engine power and our speed drop. It was acting like I lost two of the cylinders. Engine does not want to idle now. And if I do get it to start and take off. I don’t feel that kick like I do when the second set of pistons kick in. I pulled and clean the plugs. I check each cylinder for spark. They all sparked. I don’t have a compression gauge. So have not check that. I have notice if I get it started and rev the engin up and squeeze the bulb it rev up more. Any idea what it could be or where to look at next. Thank you

 

[Superboild82]

Took it in to the boat machanic. Will let you all know what he finds out.

 

[jimmbo]

That's one of the goofy 2+2 engines. Sounds like the one or both of the two always working cylinders quit. Without them the engine can't run below 1800 rpm

 

[Glastron_V210]

Simple first!

Sounds like your tank breather has clogged up...when you run for a while it starts to pull a vacuum in the tank and you can't get gas anymore.

Check the breather. also, if this happens again before you get a chance to check it out, simply remove the gas fill top and see if there is a suction sound.

Otherwise it very well could be a blocked filter or marginal fuel pump.

Chay

 

[Superboild82]

1686

 

[Superboild82]

Got the boat out of the shop and back on the water. It was a broken reed valve on one of the cyclenders.