300 Evinrude Bogs Under Load

[Li'l Toy]

I have a problem that is getting worse with my new-to-me 1985 300 Evinrude. Yesterday, after running for a while at WOT or close to it, I was idling for about 7 minutes changing passengers. When I tried to give it throttle, it just bogged. In the old days, I would say the accelerator pump wasn't working, but it seemed like even if I tried to accelerate slowly rather than jumping on it, it would do the same thing. Eventualy I got it started in gear with about half throttle, and it ran through the trouble, planed, and ran fine for 45 minutes after.

If it makes a difference, I am running a Holley Blue electric fuel pump, with a regulator. It supplies enough fuel for WOT no problem. Also, I had experienced this same type of problem in two unique situations before yesterday. First is that I could not go from minimal idle to WOT pulling hydrosliders--had to be idling along at a decent clip before hitting it to keep it from bogging. Fine for the hydroslides, not so good for an inexperienced wakeboarder. The other is that the motor has never let me power the boat onto the trailer. Always bogs in that situation.

Any ideas or suggestions? Thanks.

[Airboater]

What fuel pressure are you runing ,sounds like you mave have a float bowl leaking over during idle,they can leak at 4psi or 8 psi if the floats are set to high or have trash in them .Are the Vro's still hooked up and isthe holley on a seperate switch.

[speedracer]

Try hitting the primer when It happens again when trying to get on plane, sounds like heatsoak, this usually happens when the motor Is up to temp and then shut down for a short time then restarted. Hit the primer nest time It does It and see what happens.

[PanRonnie]

i used to own a 3ltr evinrude
also had problems starting it after shutting down for some time
put on a electric pump
i made a T fitting just before the entrance of the VRO pump
and made a return hose to the tank which was routed upwards under the cowling
it started a lot better after that
added benefit was when running near empty on rough water
the air that is sucked in the inlet hose will go in the return hose
so you won't have a surging engine

[Li'l Toy]

Airboater--truth is, the regualtor is set wherever the guy who last ran the boat had it. I did buy a new pump and regulator (but left the old regulator in place), so I can figure out how to change it and do so. I gather I should go with lower pressure, or face rebuilding 8 carbs.

The VRO pump is long gone--line goes from electric to carbs, with a low pressure limitter still in the line. Holley is on a separate switch.

Speedracer--I tried the primer on the theory that the engine was starving--kept it running real rough when it wanted to die, but didn't clean it up. I can't swear I tried to open the throttles with the primer on.

[Airboater]

Might try pulling the cover off the front of the carbs if their is one and turn the fuel pump on with the engine off and see if they might be bleeding fuel in the barrel .I had a simular problem that ended up being float levels incorrectly set and trash in the bowls.

[Li'l Toy]

Since I finaly got a cordless drill, not so much trouble to pull that front cover off. I will give it a shot. Thanks.

[Li'l Toy]

Not to derail my own thread, but how did Alva go Saturday? I really wanted to be there, but one of my sons plays football for Miami and we had a game. Sounded like it would be a fun gathering, and I would have loved to have Greg take some shots of my boat. In fact, I have to visit a client in LaBelle on Thursday, and I plan to drag the Eliminaotr with me and play a little after the meeting. No place down here to run much, and I thought I might put in West of the locks and run down to Fort Myers.

[Airboater]

Nobody went out saturday,to many locals with broken boats but a few went out sunday.Anyplace on the river is good to run but the closer yoiu get to FtMyers the manatee zones start.Most of the locals run east of the Franklin locks and there is ramps at the locks ,Alva and LaBelle ,give Greg a call if you run to FtMyers .

[HighVelocity]

Is there any chance this could be electrical. I have more experience with cars, and I have had a few that would do same thing under a load. Since timing is not an issue, perhaps a coilpack is not delivering a good spark, or weak spark. In other words enough to run it but not under a heavy load. I know that you need more spark as RPMs increase, so you can burn the extra fuel. In cars you can start at 10K volts and go up to 30K volts at 5K rpm.

I think you can check those coil packs with multimeter, they should read a certain resistance. Also check, stator or magneatto.


just a inexpensive thought, Ed

[jphii]

....Since timing is not an issue....

<!--StartFragment -->Funny, something similar happened to me yesterday. Runs fine in neutral, but put it in gear and it dies under load. I'm thinking the timing jumped, I just haven't had a chance to check it yet. Doesn't sound like fuel to me.

Why don't you think it could be the timing? It sounds more electrical to me. And timing is the first thing I'm going to check.