40 HP Evinrude problem

[Fishin_Freak]

Well my friend just got a boat, with a 40 hp Evinrude, however the motor doesn't seem to get to the RPM's it should. It doesn't bog down or anything, it just doesn't seem to get to full speed, here is the weird part, only in forward. In neutral and reverse it seems the RPM's get much higher.

I should also add it idles great and never seems to have a problem staying running it just doesn't get up and go like it should.

Any idea's?
Thanks so much in advance!


-Chris

 

[Rick.]

Re: 40 HP Evinrude problem

Check for spark on both cylinders. You may well be running on only one. Best of luck. Rick.

 

[Fishin_Freak]

Re: 40 HP Evinrude problem

I will check that, as well as compression tomorrow morning. Any other idea's?

Thanks,

Chris

 

[Rick.]

Re: 40 HP Evinrude problem

In neutral and reverse there is far less/no load on the prop than in forward. If it were on one cylinder then the problem would appear when the load is highest. Rick.

 

[Fishin_Freak]

Re: 40 HP Evinrude problem

Ok, well today we checked compression/spark compression was right around 140 for both cylinders. Plugs looked ok,got new ones, haven't put them in yet though. So we took off the air filter and housing, just too see how it looked, no problems here either. So we took it to a mechanic, he looked it over/started it and ran it for a bit. He couldn't find anything wrong, no surprise because it wasn't under load. He told us to go to a lake, and try covering one of the intakes at a time. So we get to the lake take it out and realize when it is under load that one of the cylinders stops firing. So we cover the top one and get a surge of power, so we cover the bottom one and it bogs down. So we think the problem is that the seal down the center of the crankcase is leaking. We are headed back to a lake to test in a bit.


-Chris

 

[Fishin_Freak]

Re: 40 HP Evinrude problem

Well the crankcase seal isn't leaking but the part where you check the fuel pressure is. Anyone know the name of that? On my motor its got a red valve of some sort and a gray screw on cap?

 

[Rick.]

Re: 40 HP Evinrude problem

Well you've made good progress today. I'm not sure what year your motor is but you should be able to find the part description here. Just keep clicking the right info. until you find your make, year, HP., and then model. Rick.

http://epc.brp.com/Index.aspx?lang=E&s1=f16eec34-67be-47a8-b518-82f2ece4dfbd