Evinrude E90ELEUC RPM issue while running.

[Cameron119]

Hey guys. I figured making a new thread would be best. I have a 1996 90HP evinrude. Just replaced the two coils and new spark plugs. When I first gun the throttle it goes up to around 4500RPM and sounds great, holds that for about 5-8 seconds then bogs down to 4000RPM and further bogs down to 3000RPM. If I pull the throttle back it surges like it wants to go. If I then bf o full throttle it goes back to 4500 briefly then bogs down again.

I am Stumped. To me this feels like a fuel delivery issue. When it rips at 4500RPM it sounds fantastic. I just put a fresh tank of 50:1 with premium in it incase the gas was the problem.

Any thoughts?

 

[saltchuckmatt]

Hey guys. I figured making a new thread would be best. I have a 1996 90HP evinrude. Just replaced the two coils and new spark plugs. When I first gun the throttle it goes up to around 4500RPM and sounds great, holds that for about 5-8 seconds then bogs down to 4000RPM and further bogs down to 3000RPM. If I pull the throttle back it surges like it wants to go. If I then bf o full throttle it goes back to 4500 briefly then bogs down again.

I am Stumped. To me this feels like a fuel delivery issue. When it rips at 4500RPM it sounds fantastic. I just put a fresh tank of 50:1 with premium in it incase the gas was the problem.

Any thoughts?

Tough one but 4500 is not enough....is this at full trim?

 

[Cameron119]

Tough one but 4500 is not enough....is this at full trim?

Correct it’s at full trim.

 

[saltchuckmatt]

Correct it’s at full trim.

It's not getting to wot or it's bogging down because of prop pitch. What are your prop numbers and describe your hull.

 

[Cameron119]

The boat is a 1989 Cadorette bow rider. I’d have to take a look at the prop for ya after I pull it out this weekend, this I have zero experience with. I had it out last night and if I put it at 3/4 throttle it hums along nicely at 4000RPM, but I know it wants more. As soon as I push the throttle all the way down it begins to bog down then slows down to 3000RPM and won’t go any faster. If I let off the throttle to about half I can then bring it back to 4000RPM. I have a 30 second video clip but it’s too large to upload.

I also can’t seem to see an inline fuel filter anywhere. I took a look at the line from the gas tank to the engine and it’s quite old and some of the outer sheath is crumbling. Could this be the issue perhaps? Just a thought. It’s not leaking yet.

 

[Cameron119]

Here’s some pictures of a smilar hull. It’s not my boat pictured.

 

[Chris1956]

When she bogs, try pumping the primer bulb. If that fixes it, you have a fuel delivery issue.

 

[Cameron119]

Here is the prop I have no idea how to tell the pitch etc. So before I fixed the power packs yes I could push the key in for the choke and it would open up more. It doesn’t quite do that anymore. Maybe a bit. But yes I’ll get my wife on the back at the primer bulb and when it bogs down I’ll get her to pump it to try and eliminate that as the issue. Stay tuned.

 

[Chris1956]

The prop should have a set of pat numbers on it. It may be under the trash at the prop nut or on the side of the hub.

 

[ranger335]

The boat is a 1989 Cadorette bow rider. I’d have to take a look at the prop for ya after I pull it out this weekend, this I have zero experience with. I had it out last night and if I put it at 3/4 throttle it hums along nicely at 4000RPM, but I know it wants more. As soon as I push the throttle all the way down it begins to bog down then slows down to 3000RPM and won’t go any faster. If I let off the throttle to about half I can then bring it back to 4000RPM. I have a 30 second video clip but it’s too large to upload.

I also can’t seem to see an inline fuel filter anywhere. I took a look at the line from the gas tank to the engine and it’s quite old and some of the outer sheath is crumbling. Could this be the issue perhaps? Just a thought. It’s not leaking yet.

I'd replace the fuel line and primer bulb.

 

[saltchuckmatt]

Symptoms still suggest stuff in the carb that shouldn't be there.

 

[Cameron119]

So I got the wife to pump the timer bulb constantly and she stayed level at 4000RPM for a good 5 minutes. Got her to stop and as I throttled down it started to bog down a bit. So I do believe I might remove all the fuel lines and re install for next season.

 

[Cameron119]

Symptoms still suggest stuff in the carb that shouldn't be there.

Yes do you suggest I install an inline fuel filter? I think this definitely could help the situation.

 

[Chris1956]

OK, you have a fuel restriction, air leak into the fuel line or a fuel pump that is not working properly.

What kind of fuel filters do you have? Outboard often have fuel screens. My '98 Johnny 150HPV6 has a screen under the airbox.

Some fuel tank pickup tubes have a filter hidden inside them.

 

[Cameron119]

OK, you have a fuel restriction, air leak into the fuel line or a fuel pump that is not working properly.

What kind of fuel filters do you have? Outboard often have fuel screens. My '98 Johnny 150HPV6 has a screen under the airbox.

Some fuel tank pickup tubes have a filter hidden inside them.

Good question I’d have to dig into the E90ELEUC more and there’s so much information on the internet I’m not sure where I’d find it. Maybe it’s time to pay for a technician maintenance manual.

 

[saltchuckmatt]

Pumping the primer bulb suggests fuel pump diaphragm. A good spin on water separating fuel filter is best in your situation. Any bad fuel line left after a carb clean means you have a carb that's plugged again.