The "saga" continues-a little help please!

[Ratherbfishing]

I brought my boat to have it serviced (including replacing the impeller) a few weeks ago (boy was that an ordeal) and last weekend I brought it to the closest reservoir to check on it.  IF/WHEN it starts, it generally runs fine and there is no issue so long as the throttle is kept "up".  However, if I let it idle for very long or if I run it at too few RPM's (which I did for slow trolling), it often dies.  And then it refuses to start again for a considerable amount of time-enough to where I was getting concerned about stressing the starter and battery power (would it start before I ran out of juice?).  Again, as long as the throttle  is up, it runs fine.  Also, If I shut it off myself-without waiting for it to die, it will usually start right back up again-so long as I don't wait too long. Though i'm no expert, my guess is that the check valve in the squeeze bulb is not closing property and is starving the fuel line and carburetor of fuel.  Assuming this is the case, it's a relatively cheap/easy fix (buy a new bulb and fuel line) but does this seem to be a logical conclusion?

Thanks for any help/advice you might provide!

[nixdorf]

Is the bulb firm after the engine stops?  If it is spongy, you may have an air leak in the fuel line somewhere or a bad bulb. 

 

Just a thought.

[fishnkamp]

Well usually if the fuel system is starving your problem would be at higher engine rpm. More likely it is a vacuum or air leak. Here is what i would do, some of this is just good maintenance and I want to eliminate it as a contributor. I would take the fuel line off at the engine and using the primer bulb fill a glass container with some fuel, then see if the fuel is clean, clear, no signs of water or debri etc. I would ( and have) siphoned fuel out of my tank and refilled with new fresh fuel. Check and replace your spark plugs (make sure if it was done recently that the correct plugs were installed). Due to the trouble ethanol is having on fuel lines I would replace all of my fuel lines from tank to primer bulb and from the bulb to the engine. I would replace any fuel filters that are in line or under the hood on the engine. I suggest you go to a dealer and get the new ethanol rated fuel line and get a factory Johnson primer bulb. Now I run only Merc engines, but have been hearing too many problems with aftermarket and factory Merc bulbs so instead of buying a factory fuel line and primer bulb assembly I would purchase bulk fuel line by the foot cut it to length and put good stainless steel clamps. I did the exact thing to my 6 year old boat not more than 3 months ago. Add a can of SeaFoam to your first tank of fuel. I also recommend regularly using StarTron fuel additive to all fuel added to the tank. I hope this helps to fix it 

[Way2slow]

It would have helped a little if you gave us a little info on the motor.  Make, size and year model, two stroke or four stroke, DFI, EFI, carburetor.  Each has their own unique causes of the problem you are having and there are different process for checking each.  The is no one magic bullet that's a cure all. 

Initial thoughts are it's running rich and wet fouling the plugs.  Then on top of that, you might be trying to chock/prime it to get it started, and that's just adding to it not wanting to restart.  Then it could be a 180 from that and be such a lean condition it's drying out the crankcase and you are just not getting enough fuel back in it, each condition has a separate way to check it. 

Personally, I prefer to narrow it down to the cause of the problem before I start spending bunches of money throwing parts at it.

[Ratherbfishing]

13 hours ago, Way2slow said:

It would have helped a little if you gave us a little info on the motor.  Make, size and year model, two stroke or four stroke, DFI, EFI, carburetor.  Each has their own unique causes of the problem you are having and there are different process for checking each.  The is no one magic bullet that's a cure all. 

Initial thoughts are it's running rich and wet fouling the plugs.  Then on top of that, you might be trying to chock/prime it to get it started, and that's just adding to it not wanting to restart.  Then it could be a 180 from that and be such a lean condition it's drying out the crankcase and you are just not getting enough fuel back in it, each condition has a separate way to check it. 

Personally, I prefer to narrow it down to the cause of the problem before I start spending bunches of money throwing parts at it.

25-horse Evinrude.  Normally aspirated (carburetor).  Not priming or choking it-except at the beginning of the day.  I will try to give it a little throttle if it acts like it won't start and sometimes that helps and sometimes it doesn't.

It is not, IMO, a bad idea to have a spare bulb and fuel line around anyway so I'm going to try that first.  I just have a "feeling" that this (particularly the bulb) is the culprit.

[fishnkamp]

Replace the entire fuel line from tank to engine just incase there is a restriction in the line. I think I had about $50 bucks total in bulk line, clamps, and bulb. All that equalled peace of mind.

[thomas15]

Up till last Friday, I had spent about 2 hours on the water this season. Last year when I winterized the motor it was running well. So in the spring I decided to change the water pump impeller before my first trip to the lake. This set off a series of disasters and several mini crisis that have really put a damper on this spring/summer fishing wise.

To make a very long story short, The first time out the motor idled rough and sputtered but ran fine at speed. I had the carbs adjusted but this didn't solve all of the issues which in one form or another continued until last week. I suspected a fuel problem but resisted the idea that the carbs could be dirty because the were fine last fall when I fogged and winterized the motor.

I literally changed every inch of fuel line from the tank to the carbs. I replaced both of the quick connect connectors on the fuel tank and the motor, installed new spark plugs. Rebuilt the fuel pump and rebuilt the carbs after letting them soak. I also put a 16oz can of seafoam in the fuel tank.

I didn't and couldn't do all of this at once and hence it dragged out for weeks/months. I fabricated a device to measure fuel pressure and used a clear hose to check for air in the fuel line. I also discovered that the tachometer in the dash reads about 200 RMP high at idle so I kept setting the idle speed too low.

Had it on the water last Friday it was ok, have run it on the muffs several time and all seems to be well. I'm not going to pop the cork until I have one more good trip on the water but I think I've got it. There was a lot more drama in the mix of things but it's all a bit boring so I'm just transcribing the highlights. My motor repair's greatest hits.

So to summarize I believe the biggest problem I had was an air leak somewhere in the fuel system. When I first installed the clear tube to check  the fuel line for air there was a lot of air in the line. Now there isn't even a trace of air in the fuel line. Gummed up carbs I believe contributed to making the motor run rough.

 

[frosty]

I can't say this works for outboards, but a truck for finding a vacuum leak on a car is to spray a little carb cleaner around vacuum lines and if the engine bogs down its sucking in the carb cleaner. It will get you in the right place to find the bad hose.