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LwnmwnMan2

'05 Mercury Optimax 115 hp - no power

15 posts in this topic

We had some mice get into the engine compartment over the winter.

We've spliced the wires they chewed, and replaced a plastic "tube" they chewed through.

We 'think' the tube was the vacuum tube. It was on the right rear of the engine, running from where the oil injection goes, around the back, then up and under the block that holds the spark plugs and wires.

When we start up the engine at home, we can rev the engine fine, and when we're in the lake, the engine revs fine in neutral.

However, when we put the engine in gear, we can only get up to about 2300 RPM.

The engine doesn't miss, idles somewhat fine, although if you are running "full throttle" and shut down the throttle, it'll kill. IF you just pull back on the throttle and let it slow down slowly, it'll idle.

It'll run up to about 1/3 throttle, and that's all you'll get out of it.

Any thoughts?

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You're not getting any warning buzzers / alarms / etc, are you?

Any ideas what wires or how many wires they chewed through?

marine_man

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The only time we get an alarm is when we rev the engine in neutral, it'll sound like it's hitting a rev limiter at 4000 RPMs and a warning buzzer will sound constant.

Nothing that "dings" repeatedly.

Also, the water pressure guage isn't working properly, it'll move up and down with the revs in the engine, but it'll float between 5 and 20, whereas before it was 10-28ish.

Also also, the speedo doesn't SEEM to work, but at the same time, it's hard to tell if we're really going faster than 10 mph with the lesser RPMs we're getting while in gear.

As for insurance, we're trying to figure this out so we don't have to turn it into insurance.

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What kind of splicing did you use? Was there any stuff from the mice in the air intake? I agree with you on not wanting to submit a claim, but if they (mice) did some serious damage it might be a worthwhile claim.

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Are you sure you found all the cut wires? Did you look behind the black plastic panel?

The speedo should be a seperate issue - it runs through a tube from the boat that snakes down through the motor's midsection in the moutning bracket and connects to a tube coming up out of the gearcase. Check the leading edge of the lower unit and you'll see a small hole - is there anything stuck / wedged in there? You can use an air compressor to blow air into that hole and you should see the speedo move.

The water pressure gauges (unless you've got smartcraft gauges) feeds much like the speedometer does, but it runs to the motor - you'll need to follow where the hose enters the motor to where it connects to the block to see if it's blocked, pinched, etc. I'd say there's a good chance it's pinched if you were re-tie strapping things under the hood.

How many wires / what wires were chewed through? Do the wires that were chewed through come off the main harness?

Was this boat winterized with a fuel stabilizer run through it prior to putting it away last year?

marine_man

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None of the wires we found were actually chewed through, just coating chewed off of 2 different wires, both about 1" worth.

I covered them back up with electrical tape.

Yes, we took both the black plastic panel off of the right side of the motor, as well as the top.

Now that I think about it a little harder, here's a brown wire that runs around the back / bottom of the motor, that wire was chewed off, as that was also the area of the next. This wire I completely spliced a new piece in.

We didn't tie any wires off, just patched and spliced where they were.

It's funny that you ask about if we put fuel stabilizer in it last winter. That's exactly what it acts like, other than it doesn't back fire. However, yes, we put stabilizer in. Before this boat, we had an '86 Suzuki 85 hp.

We never winterized that motor, a couple of years it sat for 2 seasons without being used in the 20 years we had it. Never an issue with it.

The '06-07 winter, we didn't put any stabilizer in the fuel in this new boat and we had no problems in the spring of '07. Last year, for some reason, I decided I'd put stabilizer in, and now we've got this issue. Murphy's law in full effect. laugh

Anyways, I've been working 18 hour days to get caught up from not working Memorial Day, and trying to keep on schedule / get ahead as I've got a trip out to the Missouri River in ND scheduled for next week for 4 days (without my boat, thank goodness), and don't want to let the 6 year old down.

I've talked to some other guys, and it seems like they're puzzled as well.

Could it be something as simple as water in the fuel? That there's enough fuel so it'll rev in neutral, but when you put it in gear, there's not enough fresh there?

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Have you changed the spark plugs?

Get a hose in the bottom of the tank and siphon some gas into a clear container. Can you see any water in the bottom or swirls or cloudy gas?

Fuel filter?

If theres chewed wires there has to be a nest. Did you pull the cover off the air box and look for a nest?

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We did not change the plugs, that's an idea, along with the tube.

I've got at most 10 hours on this motor, we've used the boat about 12 times in the last year and a half, all around Lindstrom area to get from the launch to where we fish, then just use the trolling motor.

The nest was quite extensive and quite obvious. We dug, vacuumed and cleaned it all out. It was made with the innards of an old "orange collar" type life vest that was thrown in the boat for backup.

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With something that new and expensive, I would at least discuss a claim with your insurance representative. Hopefully you took some pictures.

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No, no pictures, but I do have a call into the insurance guy just to see where my policy stands on mouse damage.

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I agree with Frank on the spark plugs & pumping some water into the bottom of a clear container on the water.

It sure seems like a fuel problem to me... like a plugged jet on a non-efi engine.. but that doesn't seem to be the problem...

One other thing - the tube that you fixed that you thought was a vacuum tube... did you splice that, or how did you repair that connection?

Have you verified that the throttle linkages / controls under the hood are travelling correctly when you advance the throttle to full throttle?

marine_man

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The tube that we replaced, we replaced the entire tube.

The first time we ran the boat afterwards, the engine "popped, hissed, backfired, a slight combination of those sounds" and then it popped the tube off, after running for 2-3 minutes, so we got some better clamps and now the tube has stayed on.

I'm making a list of all these issues, I've called in some reinforcements to help me get through the schedule to get caught up, now that I've lost both a half day today, and looks like another 1/2 day tomorrow.

Hopefully in the next day or two I can figure out what's going on.

Thanks for your help so far guys.

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Well, I thought I'd give an update.

We got tired of troubleshooting this ourselves, too much time to fix something, run it to the lake, fix something, run back to the lake, I've got other things I need to get done as well, so we ran it to a shop that I trust, knowing it's probably not going to be cheap.

Anyways, turns out there's a bad coil. I have no idea how there's a bad coil, other than I suppose it could have ruined it when we first were trying to start the engine before we knew there was mouse damage, and the chewed wires shorted out.

Also, the tube that we replaced, as the shop was running the motor, it would literally blow holes in the tube. They replaced the tube with a reinforced tube, as I just had fuel line hose on it.

New set of spark plugs, replace the water pressure guage, 5 hours of labor later and wha-la, get the credit card out, and make sure you just look at the reward points earned, right??

Anywsys, I appreciate the help.

BTW, fuel looked fine over the weekend before we brought it in, so that was one more reason I just decided to get it in somewhere and let someone that knows what they're looking at with the right tools to look at it with, take care of the issue.

Now I can get back to fishing again.... if I can get caught up with work now that the 2 mowers are in the shop. smile

You ever get that feeling like someone's out to get you??

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Glad you got it figured out... even if it was the expensive way crazy

marine_man

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