Engine Woes

whale · #1 06-22-2008, 05:19 PM

Well, I went out flukin' yesterday and today and ran into an engine problem. Being a relative newbie to owning a boat I am not well versed in outboard diagnosis. Thought I'd get some ideas first before I decide if I need to bring it to a pro.

On the way out yesterday , the motor (Johnson 115 hp) was running fine for about 5 miles. All of a sudden it started bogging down a bit and eventually it was in a sort of permanent bog down. It would run but the tach was up and down. Every once in a while it would catch and start to rev and run OK for a few seconds. Well, I was almost where I wanted to be so we limped there and drifted for fluke. Then, when I went to reposition, it ran fine every time after that. It ran fine all the way home (10 miles) also.

Along the way I had disconnected one of the 2 fuel filters I had inline and thought that the 2 filters was too much and restricting fuel flow. So, I thought everything was fine and headed out again today.

Well, same story, different day. Ran fine for a while then bogged down. After drifting for a while, it ran every time after that and all the way back to the slip.

So, it seems like a fuel flow issue but then it will run fine after sitting for a while. Any chance it is just spark plugs? I realized I didn't change them before this season. Any other ideas? The boat is in a slip so I didn't have a chance to try anything yet. It is also tough to troubleshoot due to the intermittent nature of the issue.

Please help!!

THEFERMANATOR · #2 06-22-2008, 05:22 PM

Have you removed the filters and checked them for water yet? Water can cause what you describe in there as water is to large of a molecule to pass through the element. Check your filters first. Also, was your primer bulb sucking together when this was happening?

whale · #3 06-22-2008, 06:20 PM

The racor filter has the clear bowl and there is no water in it. The boat has a new fuel tank this season so the gas is all pretty fresh (unless it came from the pump with water). The primer bulb looked normal. I found it peculiar that it ran fine both days on the way home after drifting with the motor not running for a while.

Stillrunning · #4 06-23-2008, 09:58 AM

I would still drain the sep. to see what you get.

Blue_Runner · #5 06-23-2008, 10:07 AM

Was the primer bulb nice and firm during the issue? Have a buddy squeeze the bulb while the problem is occurring to see if it clears it up.

Its entirely possible that the primer bulb ITSELF could be the problem. Check it real good for signs of dry rot (like cracks).

whale · #6 06-23-2008, 10:40 AM

When I changed the fuel tank in the offseason, I installed all new lines and a new primer bulb. Unless the bulb is faulty.....

whale · #7 06-23-2008, 10:41 AM

The first few times out this season I noticed a very slight hesitation a couple of times but it only lasted an instance and then it was fine so I blew it off.

macojoe · #8 06-23-2008, 12:15 PM

I had the same problem with my old Evinrude, it was the Ball and I had to get 3 before I got a good one, then it started again and one of the power packs let go.

But go with replacing the filter, they get clogged easy with this new gas cleaning the tank and the Racor being 10 mm.
Make sure the vent is clear.

were the hose that you replaced for the new gas??

whale · #9 06-23-2008, 02:38 PM

Yes, ethanol rated fuel lines.

Is the primer ball absolutely needed? Can I run without it for testing? I never have to use it anyway. I will reroute back to my old filter and put on a new one since I have a bunch of them and try that.

Could fouled plugs cause this?

willy · #10 06-24-2008, 11:58 PM

primer ball will cause all you are experiencing Kev, when it does it next check and see if it is collapsed on itself at all indicating a vacum situation, in other words clogged or plugged up on tank side of it or is it soft and easy to squeze indicating that it is letting air in somewhere. On my new boat went through three of them to get a good one and after that all has been fine.
you do need a primer bulb as there are times when you can lose your prime.
you also should have a in line filter under the hood of the engine, I think where the line goes into the carbs. check it for the same reason.
I do not believe plugs would cause your problem, but have you pulled them and checked their condition, as in dry wet oily and sooted up one diffrent than the other three?
My next step after checking those things would be to run her on an auxilliary five gallon boat fuel tank. If you have no problems you know it is from engine back on fuel system, if you still have it you can still have a fuel delivery problem with the fuel pump needing a rebuild kit cheap and fairly easy to do your self or a clogged carb jet or sticking fuel bowl float.
If those things come up clean then you are into taking it to a tech who can diagnose the electrical system for a timing power pack coil problem.
On my merc it did something like this as the power pack started crapping out and then would not run at all.
I don't think you have a timing type problem though as it would run crappy most of the time if not all of it. Also do not discount the idea of the tank being dirty as they can come new with crap in them and get dirty during install or have a clogged or defective pick up in them.
I am afraid like me you are going to have to slueth this one out. But if it get to that point run it in and have a pro look at it before your season flys by. It is a low hour engine and a very good one so it is going to be something pretty basic I would think.