225 Vindicator Wide Open Throttle Surge

[britt2020]

I purchased a 1998 Stratos 201 Pro Elite about a year ago. It cranks, starts, Idles and runs smoothly until you get passed about 3/4 throttle, after a bout 3-5 seconds passed 3/4 throttle it will begin to surge, very lightly at first and progressively gets worse. As soon ad you drop back down to about 3/4 throttle it goes back to running fine.

I'm suspecting it's a leak on the negative pressure side of the fuel system allowing air into the line, but that is no more than a guess on my part. There are no obvious fuel leaks, however when I pump the bulb up good and tight one of the carbs leaks fuel out of the neck. I figure this is just a sticky valve in the bowl and not whats causing my issue.

I have removed the high flow jets from the bowls and all of them were clear from debris. They were all loose when I removed them, but I made sure to get them snug when replacing and the surge still persisted.

It will still do about 55 at 3/4 throttle, which is plenty fast for me, but just knowing that there is an issue is an issue.

I appreciate any advice and direction.

 

[QOB]

You need to remove all carburators and mill and drill cleaning them all passages out. Most importantly set all floaters correctly, may need to flood them a little. If this easy process does not fix the problem, you will need a timing light and hang at the back of the boat with cowling off to detect your advanced timing to make sure all cylinders are firing and setting is correct. If so one of your ignition component is at fault if you defined surge as a slow and go fast so on and so forth!
You should see a spark jumps between cylinders when it happens. Jumping meaning firing on and off between cylinders at high rpm.
Good luck!

 

[faztbullet]

Check your fuel system as sound like fuel pressure is low. Either a air leak in lines or VRO problem. Have someone pumpthe bulb to see if it stops surging.