'94 Evinrude 88 SPL losing power randomly

[.Bennett]

I'm pretty much a nooblet when it comes to boats but I'm not new to forums so I searched!!!

I bought my first boat a few months back. Like the title states, its an '94 Evinrude 88 SPL motor and a Key Largo 172 CC boat (2000).

The first 5-6 times I had it out it ran great no problems. Had 5 adults in it and it got right up on plane and ran strong. However, the last two times I've had it out (with just me and a friend in it), it will randomly power down while cruising at 25-30mph. The motor never dies or even sputters but its like it just takes itself down to idle speed. I can return the handle down to idle speed and immediately power it back up and it goes fine again, like nothing happened.

This has only happened twice and after each time it did it, I redistributed the load in the boat and it didn't happen again. Any idea what could be the problem here? Plane issue maybe? Fuel delivery? I get no indicator lights on the console at all and the motor gives no indication of a problem whatsoever (doesn't even rev like seems would happen if it were a plane issue). Its almost like it just powers itself down lol

Searched and came up empty so any help would be appreciated. Thanks!

 

[tashasdaddy]

Re: '94 Evinrude 88 SPL losing power randomly

sounds like the fuel tank vent is close or blocked.

 

[.Bennett]

Re: '94 Evinrude 88 SPL losing power randomly

sounds like the fuel tank vent is close or blocked.

hmm, where/how does one fix this? Again, I'm pretty much a n00b so I apologize.

edit: Is it on the side of the boat thru the battery box? I remember breaking off the top part of a plastic top (similar to aerator top) right there because it got caught on a spacing between the rubber bumpers at the ramp. The plastic top/screw top smells of gas. I'm guessing thats it. If so, how do I make sure its venting properly?

 

[SparkieBoat]

Re: '94 Evinrude 88 SPL losing power randomly

also go to an auto parts store and get a spark tester. and check all of your coils.
should produce a blue spark with a 1/2 gap. A weak coil can cause problems also..just blow through your vent tube to test for obstruction, remove your gas cap when you do it.

 

[.Bennett]

Re: '94 Evinrude 88 SPL losing power randomly

also go to an auto parts store and get a spark tester. and check all of your coils.
should produce a blue spark with a 1/2 gap. A weak coil can cause problems also..just blow through your vent tube to test for obstruction, remove your gas cap when you do it.

the venting issue seems to make perfect sense because of the timing of it. No issues until I broke that cap.

Now as far as blowing into it, what if there are plastic fragments in there? I don't really want those going into my tank do I?

 

[wilde1j]

Re: '94 Evinrude 88 SPL losing power randomly

The purpose of the vent fitting is to allow venting while keeping water out (that's why the opening faces aft). I would replace the fitting with a metal one. You don't have to worry much about the pieces. Unless the fitting or hose has become blocked, I doubt it's the cause of the power down, but there are other tank related possibilites, such as crap blocking the tank pickup, etc.

 

[.Bennett]

Re: '94 Evinrude 88 SPL losing power randomly

The purpose of the vent fitting is to allow venting while keeping water out (that's why the opening faces aft). I would replace the fitting with a metal one. You don't have to worry much about the pieces. Unless the fitting or hose has become blocked, I doubt it's the cause of the power down, but there are other tank related possibilites, such as crap blocking the tank pickup, etc.

well upon blowing in it (with gas cap off), it did feel like there was a small obstruction that gave way (very small though). I did this several times and each time it kinda blew back at me. Normal?

And my tank is under the floor (30 gal) so what's the best way to make sure there isn't any "crap" blocking pickup?

 

[wilde1j]

Re: '94 Evinrude 88 SPL losing power randomly

Blow back is normal.

Built in tanks are a problem. The only useful access to most is thru the gas gauge flange (i.e. remove the gauge so you can see). This is not bad if the boat builder put an inspection port in the floor to give access. Otherwise not worth it to try, since it usually requires cutting holes in the floor. Before doing anything radical, I would try hitting the choke when the RPM's drop or squeezing the primer ball. If RPM's come back immediately, you have a fuel delivery problem (bad fuel pump, air leak into suction side of pump line from tank to motor, anti-syphon valve bad, etc.)

 

[.Bennett]

Re: '94 Evinrude 88 SPL losing power randomly

Blow back is normal.

Built in tanks are a problem. The only useful access to most is thru the gas gauge flange (i.e. remove the gauge so you can see). This is not bad if the boat builder put an inspection port in the floor to give access. Otherwise not worth it to try, since it usually requires cutting holes in the floor. Before doing anything radical, I would try hitting the choke when the RPM's drop or squeezing the primer ball. If RPM's come back immediately, you have a fuel delivery problem (bad fuel pump, air leak into suction side of pump line from tank to motor, anti-syphon valve bad, etc.)

I do have an inspection port above the tank actually. This problem also coincided with a new tank of gas but I dunno if thats just a coincidence.

At any rate, I'm getting it tuned up in a week anyway so I'll prolly just mention it and see what they can figure out.

 

[zman_88]

Re: '94 Evinrude 88 SPL losing power randomly

My '89 Johnson 88SPL had the same problem. Turned out to be a bad coil intermittently causing one cylinder to get no spark. The manual has a procedure to check it, otherwise replace all four. Let me know if this works.

 

[.Bennett]

Re: '94 Evinrude 88 SPL losing power randomly

My '89 Johnson 88SPL had the same problem. Turned out to be a bad coil intermittently causing one cylinder to get no spark. The manual has a procedure to check it, otherwise replace all four. Let me know if this works.

Okay, so when I dropped it off today at a local Marine shop to have it tuned up, I mentioned this issue to the repair guy. He said he wasn't sure till he looked at it but it might be a "burned piston."

Anyway, he's prolly not gonna get to it till tomorrow so I won't know till he does but this does NOT seem right to me. Like I said, I'm not familiar with boats too much but I'm very familiar with car engines. I don't see how a burned piston would only manifest itself in powering down a random times and nothing else.

Like I said in my initial post, there NO other signs of a problem. Starts/idles/powers up fine. No noticeable loss of power (other than when it randomly loses it, obviously lol) or extra smoke. And I get no warning lights on the console.

This is a seemingly reliable shop from what I've heard but I want to make sure I'm informed in case they are trying something squirrelly on me.

Help me out, ya'll!!

 

[.Bennett]

Re: '94 Evinrude 88 SPL losing power randomly

no opinions?

 

[emdsapmgr]

Re: '94 Evinrude 88 SPL losing power randomly

Why not wait to see what the mechanic finds, then post the results?

 

[.Bennett]

Re: '94 Evinrude 88 SPL losing power randomly

Well he found nothing and gave it a tune up so I thought that was interesting. He cleaned the carbs, changed the plugs and the fuel/water separator filter.

Took it out tonight and it ran awesome for nearly an hour (just cruising the river at about 3500-4500 rpms). Then when I got to fishing, I switched spots several times within a 15 minute period and shut off/started the motor twice within a 10 mins. I go to leave for the night and it wouldn't start!!

Took me 20 mins to get it started. Not sure what the issue was but after checking the fuel line (not flooded) and squeezing the primer ball still got nothing. Finally after letting it sit for a while it fired up.

BUT after that, it reverted back to its powering down randomly ways!!!! WTF? I couldn't stay at 35-4500 rpms more than a couple minutes without it doing it!!!

I really don't understand this. It seemed to have gone away until the starting issue (went nearly an hour at high rpms without it doing it) when I killed/started it frequently.

I specifically asked the mechanic to check the fuel tank venting and coils and he wrote no notes regarding either so I'm guess that checked out.

Any more ideas?

 

[SparkieBoat]

Re: '94 Evinrude 88 SPL losing power randomly

you could have a coil/power pack that goes in and out or you got fuel issues..I am leaning toward the coil/power pack issue..does it have 2 power packs on that model??.. if so it also could be the stator..I got a friends 1984 185HP now that had a bank go out and it was the stator,,I OHMed the 2 wire plug going to the power pack and it was 0..the other side was 480 or something like that I think..but when I switched the wires the other power pack went to working.

 

[.Bennett]

Re: '94 Evinrude 88 SPL losing power randomly

you could have a coil/power pack that goes in and out or you got fuel issues..I am leaning toward the coil/power pack issue..does it have 2 power packs on that model??.. if so it also could be the stator..I got a friends 1984 185HP now that had a bank go out and it was the stator,,I OHMed the 2 wire plug going to the power pack and it was 0..the other side was 480 or something like that I think..but when I switched the wires the other power pack went to working.

I honestly don't know, I'm still pretty much a n00b like I said. I'll ask the mechanic how well he checked it out/if he thinks this is the issue. I appreciate the reply.

 

[.Bennett]

Re: '94 Evinrude 88 SPL losing power randomly

you could have a coil/power pack that goes in and out or you got fuel issues..I am leaning toward the coil/power pack issue..does it have 2 power packs on that model??.. if so it also could be the stator..I got a friends 1984 185HP now that had a bank go out and it was the stator,,I OHMed the 2 wire plug going to the power pack and it was 0..the other side was 480 or something like that I think..but when I switched the wires the other power pack went to working.

I was doing some further reading and is it possible this could be contributing to the starting issue I briefly had as well tonight??? Seems like it could be related.

 

[jonesg]

Re: '94 Evinrude 88 SPL losing power randomly

It does sound like a heat related ignition component failing.
Take a timing light with you and see if its dropping spark when it gets balky.

Meantime a spark GAP test with tester set at 1/2 inch gap will show a possible weak ignition. Adjustable gap testers are less than $10 at auto part stores.

Power pack and coils are the usual suspects.

 

[emdsapmgr]

Re: '94 Evinrude 88 SPL losing power randomly

That model did not have the SLOW feature. Agree with Sparkie and Jones-could be an ignition problem. Check all four plugwires for spark when the engine starts to slow.

 

[.Bennett]

Re: '94 Evinrude 88 SPL losing power randomly

That model did not have the SLOW feature. Agree with Sparkie and Jones-could be an ignition problem. Check all four plugwires for spark when the engine starts to slow.

what is that?