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I have a 1990 Evinrude 25 hp motor on my boat. Lately the engine started surging when ideling. That progressed to surging while planned which led to no longer planning . At times it acts like it is not getting gas at other times it just dies while trying to plane as if something grounded out the spark. Admittedly I am a poor mechanic but I have checked things like compression (125 psi at each cylinder) and if fuel was getting to the fuel pump. What do I look for now?
clean the carb.
you might want to check your fuel line !!! if its the grey fuel line replace it and the bulb !!! get your fuel line at a auto parts store it will by rated for ethanol !!!
I did check the fuel line. It is not gray and if I pump the bulb fuel comes out the hose.
ibmack do you mean remove the carb from the motor and clean or just drain the bowl?
The carb needs cleaned
i take mine out and clean it. it is quite simple and doesn't take but around 30 minutes to get it out and put it back together once you know how. just type in your engine to google such as "cleaning carb on mercury 2009 20 hp 4 stroke", or whatever yours is and watch a couple of you tubes. you will be a carb expert shortly. buy a can of carb cleaner before you start. cheap fix for sputtering engines.Quote:
Originally Posted by crappie wrangler
I'm on the same page about cleaning. Fuel will come out of a bad fuel line. If you didn't put it on the motor, replace it. They give no outward sign of what's going on inside. It's the inner layer that goes south. So take the carb off and work over something white so that you can see anything that might come out of it. While you are in there, replace needles and seats and a fuel pump is cheap too. When my fuel line went, at 14 months old, the inner liner broke apart and small black chunks were found in the bowl and in the jets. To cut it short, you'll need a carb kit and the needles and seats and a fuel line and filters(2) to take any chance of missing something out of the picture. Having an exploded view of what you're working on is a help, but the motors are simple. While at the store, pic up a couple of cans of Sea Foam and run it religiously about every 5th tank or so, at least half a can, and it will keep the fuel demons at bay. Has worked for me and many others for years. If I have a fuel problem, and i have a hard time figure it out, I do what I've recommended and eliminate any chance of it not working when I'm 2 miles east of BFE at dusk. Sorry to ramble.....Skeet.
Might not be your solution, but my dealer proved it. ou ma have a bent propeller, try a spare.
It might be getting air into the fuel line. Once it's running the line from the fuel pump to the tank is no longer under pressure. If you pump your primer bulb and watch real close under the cowling you might see a real small leak... oily spot can be a tip off too. Also a gasket leak on the carb can let air in. About any older motor is ready for a carb rebuild and fuel lines...but your specific problem sounds like air getting in. Also sometimes you have more than one problem.
I have not started taking it apart yet because I was waiting on a repair manual that I had purchased to arrive. While I am not a real good mechanic I can follow instructions. The manual arrived yesterday but it was the wrong one. I spent an hour on the internet this morning looking for the right one. Finely found an OEM manual for that exact engine and ordered it this morning. As soon as it arrives I will tackle the job. Thanks to everyone for all the advice.
Something that might be noteworthy. Your motor has an overheat protection circuit that when active, will only allow about 2500 rpm. When active, the engine will 'surge' as it exceeds that rpm, drops below and again accelerates above. It will go into a rhythmic cycle until the throttle is dropped to the point where rpm no longer exceeds 2500. Having said that, if that's what is happening, the engine is either overheating or you have a failed component in the circuit.
I replaced the impeller and that made no difference. When I began to suspect the power pack or voltage regulator I took it to a repair shop. After that I searched the internet until I found an OEM manual for that motor. Manual should arrive any day now
I had the same problem you posted and I pumped the bulb and fuel comes out , but that was not the problem !!! when the motor was running the inside of the fuel line was collapsing restricting the fuel flow !!! replace the fuel line a bulb runs like a champ !!!!!Quote:
Originally Posted by crappie wrangler
Have had OMC and Brunswick Corp outboards of a bunch of varieties through the years.Currently happen to have a 25 Evinrude.Evinrude fuel lines have always been notorious for leaking air and causing problems.This generation and the one prior.The other guy saying you need to try another line is dead-on. After that I would agree with a carb kit.
Have you changed and gapped your plugs?Sea foam I like but know a couple different guys who had problems after using the green Sta-bil marine additive. I also want to agree with the guy who says it is not easy to evaluate your fuel line....Been there,done that
Quick story-Many years ago had a 61 Johnson 10 horse.Ran great at first but would eventually sputter after going a distance.Always had tools with me.Would remove the carb.Disassemble/reassemble and before the day was over fight and fight it.Eventually took it to a dealer who replaced both coils.One of the two coil's insulation was breaking down .Once it got hot,it would short to ground and misfire.......Good Luck