My motor starting acting up by intermittentaly loosing fuel when running. Engine would surge. So, I changed plugs, check wires and coils (all good), prebuilt LP fuel pump, removed and cleaned EVA tank and internal filters, changed inline fuel filter, water / fuel seperator, primer bulb and lines, fuel pressure regulator and lines and it still surges after about a 4-5 min run WO. Idles fine, runs good, runs at 4000 rpm OK. ????? What am I missing??????? Any help would save my life at this point, so frustrated.

Are you sure it is not getting hot?

Wayne

Obstructed tank vent, fuel pickup, sticking anti-siphon valve (all permanent marine tanks have them), etc. Can you rig another tank for it to run from as a test? (think portable 6 gal. tank)

I'm going to run it tomorrow to test output pressure of the HP pump and run it off a pony tank.

Let us know; inquiring minds are curious!

Separated boat and engine by using a pony tank. Its an engne issue. It feels like the LP can't supply the HP pump with enough fuel. I'm going to check the water supply lines to the LP pump. New HP ordered just as a precaution.

Sounds like progress - at least to the point it IS the engine. Keep us posted!

Here's what I found yesterday. I dropped the lower unit and found the impeller had three paddles left on it. There's a plate that goes in the vertical shaft base that was 30% gone (aluminium L plate). I have no idea what it does. I believe it deflects exhaust. The impeller pieces where stuck in the housing restricting water flow. It is my believe that the LP fuel pump was not cooling enough causing fuel boil thus preventing the EVA tank (it houses thr HP pump) from filling at high rpm`s. Changed HP pump which I had to use the old base and screen because the new one had a hole in the screen and was not removable. I ordered a impeller kit and a new plate. I will install a d assemble then back flush the system. I am very confident that this was my issue all along.........OVERHEATING. learned my lesson, I will be changing the impeller regularly from know on.

Good deal. You really dug into it! What saved you a lot of $ is being smart enough to not ignore the issue in the first place - and being handy enough to tear into it. Long term, that would have probably ended up cooking the engine for people who ignored that there was an issue.

Well, I good and bad news. I replaced the impeller and associated components. Excited to finally get this thing fixed. Went to install lower unit, drive shaft slipped just fine, shift linkage belt good, had a out 1/2 " to go, so I started the bolts and screwed them on. Almost right when......big crack heard. Dropped down lower unit and found shift shaft bent. Ordered new shaft and associated components. "$178.00. Don't know how to remove and replace e shaft. I have Mobil Marine from Collin County going to help out. $300.00 to do the job, anyone use this guy?