Thread: Motor is losing it's prime..PLEASE HELP!!

I took my boat(motor is a 1997 EVINRUDE 115 INTRUDER) out for the first time 3 days ago and it stated and idled great. It even ran good through mid speed. But when I gave it w.o.t it started to spuder a bit. I took it home and drained all of the carb bowls and added some seafoam. I took it back out today and it started and idled great and would even take off fine on acceleration but soon after it would die. I checked the bulb and each time it had lost it's prime. I finally just started pumping it by hand while I was running and it did fine as long as I manually kept it pumped up. Could this be a fuel pump issue or is there anything else I should check. When I prime it the bulb gets tight and does not to appear to be leaking and does not blead down. Thanks for any advice.

Yup, your fuel pump needs to be rebuilt.

My fuel pump kit was only $10. Iboats.com offers parts if you don't have someplace to get them.

Originally Posted by skeetbum

My fuel pump kit was only $10. Iboats.com offers parts if you don't have someplace to get them.

Was it a difficult repair? Does this pump also pump my oil(VRO??)?

Check the O-rings in the gas line connectors. I've had 'em to crack (look close and you can see it) causing the same problems on my 50 hp. It'd idle great and run half throttle good, even come out of the hole, but get on plane and she'd die. All I did was change out the connector. Hope you find your problem.

The fuel pump is very easy to rebuild.

Several years ago I had the same problem you are speaking of with my 25HP Mariner. Some trips the motor would run fine and the net time out you would have to pump the fuel bulb constantly to keep it running. I checked everything I could think of ,o-rings, checkvalve, fuel pump, hose clamps, gaskets everything to do with the fuel delivery system. I found nothing that would indicate a problem. One day after a trouble filled trip, I decided that I waS GOING TO FIND THE PROBLEM OR DESTROY THE MOTOR TRYING. I started with the fuel tank planning to check everything up to the carburator. When I removed the fuel line connection from the tank, the pickup tube hung on the side of the opening and twisted slightly. It was loose and I guess the less fuel that was in the tank, the more it would slosh around and cause the pickup tube to move and loose its prime. Removed it ,wrapped the threded section with teflon thread tape, reinstalled, tightened and to this day have never had any more problem... May not be your problem but would be worth a check, good luck...

Just replaced the gaskets on my fuel pump. 90hp Merc. Not too hard of a job. Tried to get it apart w/o taking all the lines lose at first, but soon realized it was much easier to get it off and gaskets changed w/ them disconnected.

snds like fuel pump...but start at the vent and work your way to the engine. Check everything. Make sure its venting...make sure it has a good pick up and its working...check your hose, connections, and bulb. A bad bulb can cause this too. Those pumps aren't very strong. Thats why you have a bulb in the first place. Check all your under cowling hoses. Check filters. Then do the pump. They are easy also. Most are just diaphram pumps. BE SURE to follow directions on how they go together. Also, if you order from iboats or a place like that...make SURE there isn't a recall or changed part or discarded part. Ran into that with a Blackmax I did. Got kit from iboats...tried to rebuild but parts didn't all match up and ruined kit. Went and got a Merc kit and it had a paper talking about the part change...the sierra part from iboats did not. Just some FYI so you don't have to buy extra stuff. Rule out easy and cheap stuff first.

I agree with scrapper, you got a fuel delivery problem, and it sounds like a pump issue, but start at the tank and do the pump last as many things can look like a bad fuel pump.