Evirude 15hp won't accelerate past about 1/2 throttle

[Steve079]

Have a new to me '85 Evinrude 15 hp. Friday, before the purchase, the owner and I put it on my boat and ran it. Ran great. He kept his gas tank. today, I hooked my metal tank up, it started second pull, idled nice but when I opened it up it just would not rev out. Gets to about half, and just won't pick up speed. When I rolled the throttle off, it died, but started first pull.

Idles great takes off nice, but just flattens out. I'm thinking my fuel supply line is to blame. No apparent leaks, but I had to bend the tab where the line connects to the motor to get it to latch on. It does have clamps at the fuel bulb, gas filter, and at each connector. I check the screen at the fuel pump, it was clean. I also siphoned some gas out of the bottom of the tank to check it, no debris. It also has a trolling plate on it. No means to lift and latch it, uses spring pressure, and the prop wash to lift it.

I'm going to try the tank I tested it with tomorrow and see if that makes a difference.

What do you all suggest?
Thank you in advance

 

[Daviet]

Re: Evirude 15hp won't accelerate past about 1/2 throttle

Have you checked compression and spark on both cylinders?

 

[raczekp1]

Re: Evirude 15hp won't accelerate past about 1/2 throttle

if you accelerate at Neutral, so there is a rev neutral limiter,

second problem: run on 1 cylinder only(spark plug, spurk plug boot, no lead to coil,bad coil ground,

third: dirt in the carb, dirt in fuel pump filter

 

[Bob_VT]

Re: Evirude 15hp won't accelerate past about 1/2 throttle

It sounds as if you are on;y firing on 1 cylinder (common mistake)........... it will sound perfect but no power.

As stated above....... I would be hunting for a good solid spark on both cylinders.

 

[AlTn]

Re: Evirude 15hp won't accelerate past about 1/2 throttle

if it ran great on his tank and not on your's...seems your logic is correct to me..is your tank vented properly < run with the cap off for a test >, inline filter clogged, water in fuel, etc.

 

[Steve079]

Re: Evirude 15hp won't accelerate past about 1/2 throttle

I ran some fuel through the line, after I disconnected it at the fuel pump. Screen was clean, fuel flowed freely. I agitated the tank, then siphoned a pint from around the bottom and corners of the can, looked nice and clean. I did pull a plug wire off one of the plugs to see which plugs he was using, MAYBE I did not get it on all the way, I'll check that out. I thought about the can not venting properly, it's an original OMC style can as I was slogging along, I loosened the cap for a second, no change.

I was reading thru a series of articles here, "Leroy's Ramblings" and if not my #1 thought, fuel supply line, then I'm thinking maybe the throttle twist grip has jumped a tooth or two.

One other thing, when it was attempting to run with the throttle wide open, it sounded like it was lugging under the load, when I backed off it ran cleaner. I wished I had pulled a plug right then, but made the mistake of not having all my tools,

Thanks all for the suggestions, I'm going to replace the line and fuel bulb, and see if that helps.

 

[Steve079]

Re: Evirude 15hp won't accelerate past about 1/2 throttle

Well, problem solved. Chaulk this one up to my being a newcomer to the world of outboards. I had a bad fuel bulb, It was leaking back into the tank. A mechanic friend of mine diagnosed it rather quickly. As we live in a very small town, with very limited parts availability, he loaned me one to test it out, and the motor ran nice. I am most impressed with its willingness to troll down to Kokanee trolling speeds, with no stumbling and then just get up and go, once I pulled my lines in. Yes, I was fishing as I played with the idle speed and mixture adjustment knob. Got a nice rainbow for the grill, as a n extra bonus.

Thanks to all of you who helped out, it was greatly appreciated!