Boat motor problem

[gillman]

When out yesterday and when i open my motor up it didn't open up all the way, about1/2 open. Well it had done this once back in May and then open on up. So I went on thinking it would go on an open up but it shut doun to a flast idle. So I turn around and headed back to the Dock and after going about 1/2 way, 200 YDS, she went on and opened up and was OK from there on. Does anyone have a ideal what's going on? It's an 1984 Evanrude 115 carbed. engine.

[Fishin is life]

Sounds like it could be spark plugs...how long has it been since youve changed em?

[gillman]

Put in new plugs last winter when i rebuild the engine. I never though to tell, but the engine didn't miss one lick. The plugs most likely need changing because i mix my oil and sometimes it pretty rich. My Auto-Oiler wasn't pulling out was the reason my motor went down last year.

[Fishin is life]

i had my plugs go bad back this summer and my boat never missed i just couldnt get full power....sometimes id get power and sometimes itd struggle to set up on pad....i could be running down the lake with it wide open and all of a sudden itd gain power and take off...plugs would be the easiest and cheapest way to start lookin for the prob....pick em up for a couple dollars at your local parts house

[HURRICANEBOB]

When out yesterday and when i open my motor up it didn't open up all the way, about1/2 open. Well it had done this once back in May and then open on up. So I went on thinking it would go on an open up but it shut doun to a flast idle. So I turn around and headed back to the Dock and after going about 1/2 way, 200 YDS, she went on and opened up and was OK from there on. Does anyone have a ideal what's going on? It's an 1984 Evanrude 115 carbed. engine.

I had a similar problem with my Merc. And it sounds like this happens intermittently same as mine was. In my case, it turned out to be a bad fuel line. There's a little check valve in the fuel line right after the ball you pump fuel pressure with. In my case, that little checkvalue had some gunk on it, and it was every once in a while hanging up and blocking either just a little fuel (I could get 3/4 throttle), or a lot of fuel and I couldn't get much over high idle. Swapped the whole fuel line out and it solved it.

Other things to check:
1. Is there any debris in the fuel tank? It could be intermittently block the fuel pickup in the tank.
2. Are you sure the vent on the fuel tank is working okay? This summer the vent on my tank got just a little closed more than normal due to engine vibration. I took off down the lake wide open, all running okay for about 10 miuntes, then the morot started to gradually slow down. Finally got to a rough idle even with throttle wide open. I open the fuel tank compartment lid, and was surprised to see my plastic fuel tank was sunk down severely in the middle from suction/vaccuum that built up in the tank. The vaccuum created was so strong fuel could not flow to the motor. I opened the vent, heard a loud whistle of air, the tank expanded back to normal shape, and the motor ran fine after that.
3. Might also be a fuel pump that is dying. This article I found for you does a better job explaining it than I can: link is: http://forums.iboats.com/showthread.php?t=203544

Article follows: This guy had the same problem you did, swapped out the pump, and problem went away according to teh article.

I have a Johnson 110 that was acting the same way. Turned out to be a bad fuel pump. When you disengage the VRO system it seems to put strain on the fuel pump. (VRO pump and fuel pump being encased in one). Remove the old fuel/Vro pump and install the old style single pump. Problem should be gone.

The old style fuel pump apparently works by vacume. (no electric plug). Fits just in front the starter, against the block. You should have a brass plug blocking it up now, with two threaded holes (one on either side). Just take the old pump off. (Don't be afraid, it's not that hard). Mount the new (old style pump) on the engine and re-route all your fuel lines to fit. (Line from fuel tank to the "in" side, line to carbs to the "out").

The old pump is much larger than the old style one you'll be replacing it with. The new pump won't have any electric hookups either. Hard to believe the old style (about the size of a deck of cards), with two fittings (one for fuel in, one for fuel out) can replace all that you'll be taking off. Especially since it's not mounted in the same place. However, it works. Trust me, I re-did mine not long ago. Runs great now.
Starts faster, even seems to run better. Maybe I was just used to the way it was running before, when the pump was going bad. Good to go now though. Good luck.

[markmac60]

The old pump is much larger than the old style one you'll be replacing it with. The new pump won't have any electric hookups either. Hard to believe the old style (about the size of a deck of cards), with two fittings (one for fuel in, one for fuel out) can replace all that you'll be taking off. Especially since it's not mounted in the same place. However, it works. Trust me, I re-did mine not long ago. Runs great now.
Starts faster, even seems to run better. Maybe I was just used to the way it was running before, when the pump was going bad. Good to go now though. Good luck.[/QUOTE]

****, now thats a response to a guys request. That's why I like this website. Great job.

[kydonky]

When out yesterday and when i open my motor up it didn't open up all the way, about1/2 open. Well it had done this once back in May and then open on up. So I went on thinking it would go on an open up but it shut doun to a flast idle. So I turn around and headed back to the Dock and after going about 1/2 way, 200 YDS, she went on and opened up and was OK from there on. Does anyone have a ideal what's going on? It's an 1984 Evanrude 115 carbed. engine.

A quick easy was to check fuel line problems would be to connect a 6 gal portable tank with fresh gas and run that for a bit to see if it occures again. Plugs are a cheap investment. Hard to test a motor with dog ears since there is very little to no load on the motor. Had a freind with a old 40 johnson had a similar problem. I advised him to let T-boat marine (long out of business now) look at it. Instead, he let another half mechanic friend work on it. Ended up distroying the carb by drilling out jets.

In the end the problem was the fuel hose bulb sticking.

Good news is that you probably do not have a major problem as you have good compression and everything is working right "most of the time" If a quick fix does not work (fuel line, plugs) I would take it to a omc mechanic.

[gillman]

Thanks Guys, I'll change Plugs, sure it needs them, and go from there now that i have an ideal. Fuel pump does ring a bell, the thing has been hard to start for a long time. I will have to start it over and over 6 or 7 times before it would run some times, away at lest 3 times. Thanks again

[HiDefFisherman]

When out yesterday and when i open my motor up it didn't open up all the way, about1/2 open. Well it had done this once back in May and then open on up. So I went on thinking it would go on an open up but it shut doun to a flast idle. So I turn around and headed back to the Dock and after going about 1/2 way, 200 YDS, she went on and opened up and was OK from there on. Does anyone have a ideal what's going on? It's an 1984 Evanrude 115 carbed. engine.

Hey Gillman,

My boat was doing something similar. When I had it opened up, or even when I was just taking off, it seemed the motor would lose about 1,000 rpms and would take a long time to get to plane. If I was on plane, it would just rev down, and I'd lose some speed, but then for no reason it would just fire right back up.

Just an FYI, I have a 2002 Opti max (225).

I had it down to Jet-a-Marina for repair. It took them a while to find the problem, but they got it fixed and it runs great now. They said it was a "module" that controled something to do with the rev/fuel, and they also had to replace some type of plug. They also went ahead and changed all my plugs, but they did that first, and it had no real affect.

Sorry I am not more technical, or mechanical I guess, and I can't be more specific. The fix was about $500, but definately worth it. It was sure nice to have full power back on the water.

Good luck,

HDF

[gillman]

A man don't need to be a mech.to tell his exspearance or ideal thanks a sack full. I worked on D9 Cats to 966 farmall's but the boat engines are a differant animal. I'll like the guy back a post or two, ask a question and you will get some help.