Engine problems

[Clboating]

Have only had my boat out a few times this year. Have a problem with my 2002 mariner 90hp 2/s. The engine ran perfect then started to splutter at top speed but i can come off the power, go along for 30 seconds/ a minute then go back to full and its fine for abit before it spluttered again. I had some advice what to do so changed fuel leads, think i dont have any air leaks, changed spark plugs and fuel filter. Now it starts fine but splutters on low revs but it seems fine on top revs any advice would be great as this is my first boat. Thanks in advance...

[breezeblock]

sounds like a choked jet in carb

[Festinghouse]

the best thing i ever bought for my outboards has been an ultrasonic cleaner - it may be a faff, and to look at the carbs may seem clean, but with a bit of practice you will get the hang of removing and stripping the carbs. warm water and a bottle of tesco's distilled vinegar in the ultrasonic cleaner for half an hour works wonders

[9D280]

When you say changed the fuel hose what size did you get?

I choked an old yam 55 with the carryover 2 foot of 1/2" dia hose from my old 25.