Here's my problem I start up the engine it runs smooth in idle. I put it in gear and everything is fine while going slow. When I try to go 2/3rd throttle it just won't open up runs at half speed. After about 10 minutes of trying to get the engine to open up it starts to stall out and it's very hard to start. Sometimes I have to wait 15-20 minutes to start it up but will run very ruff and stalls out. Most times when I start it up I have to shift it quickly into gear in order for it to go. When I slow it down almost to a crawl it will stall. I recently had a water separator installed. What could be the problem? Any suggestion? Thanks in advance!!!