Motor Losing Power/RPMS

[craazyboutbass]

Well my tracker 90hp from Mercury Marine hasn't been running good at all lately. Lately it has been taking longer for it to plane out, but once you plane out it will pick up speed like normal... then gradually lose power. Then you get to the point whereit slows down the more you trim the motor up. You can trim the motor all the way down, it will pick up again... trim it back up then it will lose its speed once again.</p>

I checked the spark plugs and theyare alright. Have not changed thefuel filter though in a while. </p>

I'm thinking that it can be alot of different things causing the problem. Could be clogged carbs. clogged fuel lines? Something wrong with the cylinders or pistons? The motor does idle just fine, seems like it doesn't want to work off that 2 and 3rd cylinder/piston or carb really well. Just wondering if any ofy'all have experienced anything like this and figured out what was causing allthe trouble? </p>

Motor will run, just not great... use to get it up to 55-60mph when it ran great, now 45mph is top speed, but once it slows down when it loses the power we're only going 35mph or so. It's a little aggravating </p>

 

[dtw2]

i would say you have some bad rings or grooves in the piston walls

 

[dtw2]

also wouldn't run it anymore to you find problem, doing a compression and leak down will tell you about the piston and rings.

 

[stratos21xl]

what kind of fuel are you running in it...Ethanol or non-ethanol?

 

[craazyboutbass]

Usually ethanol now... the Phillips 66 with subway on the way to Parksville use to be ethanol free until this past year emodoh I always run seafoam or a fuel stabilizer when getting ethanol though.

 

[craazyboutbass]

It's the 2nd and 3rd cylinder/piston that seems to be having trouble, spitting out less oil and gas than the top one when I checked it. First one (top one) is going along normal. I mean, the motor idles fine (which would have to deal with 1st cylinder/carb/piston I think) but once you step on that gas, it starts the trouble. So I think its something to do with the bottom 2 cylinders or pistons. I know nothing about this stuff really. Im good with the simple problems, but this is something I dont think I'll be able to fix. I will probably have to get someone to work on this one for me. Willing to take some more suggestions as to what it could be, even though it probably wont help me fix the problem myself. Thanks guys

 

[stratos21xl]

I would definitely check the fuel filters. I've seen Ethanol eat the rubber off the inside of the fuel lines and cause the filters to clog up causing fuel restriction problems. How long has it been since you changed the spark plugs. I would look at them closely and compare them, if you have one or two that are really dark or really light it could be a carb issue. Another easy thing you can do is take a 5 or 6 gallon tank with some good gas in it and disconnect the fuel lines coming from the boat to the motor and hook the external tank to the motor and run it. If it clears up and runs fine, it's in the gas tank or fuel lines going to the motor, if it doesn't clear up then it's something on or within the motor.

 

[EricM]

The issue with the trim angle makes me think carbs. PM wretchin2. James will have at least a good idea of where to start looking. Hope it is a simple fix for you!

 

[craazyboutbass]

Thank you for all the suggestions. I did check the spark plugs when I checked the cylinders, they looked okay to my untrained eyes. Bottom 2 cylinders spitting out way less fuel/oil than the top one. So I know it's something within those cylinders/carbs or pistons. I would hope that the bottom 2 carbs just need a good cleaning.

 

[craazyboutbass]

EricM - 2/3/2011 9:07 PM The issue with the trim angle makes me think carbs. PM wretchin2. James will have at least a good idea of where to start looking. Hope it is a simple fix for you!

</p>

I haven't had the carbs cleaned in about 2 years. I did get the advice for my motor, to get the carbs on it cleaned every year or two. I already have a couple cans of carb cleaner, my buddy was going to come over and show me how to do it a few months ago, but we just never got to it. Would love to get her running good again, not fun riding back up the lake the other day with it running as bad as she was! emoBang </p>

 

[SethColeman]

I feel your pain we are gonna work on my carbs tomorrow am and hope that fixes my problem.

 

[wrechin2]

I have seen those have broken/cracked oil lines and causing the fuel pump to have issues. The simplest thing will be to do a leakage test on it to determine the health of the engine. I will let you use one of my leakage testers (pick up at Crown Dodge) if you have access to compressed air or you can take a road trip tp "DUNVegas" and I can do one for you real quick. Don't trust a compression test. Here is why....

http://www.chattanoogafishingforum.com/forums/thread-view.asp?tid=50110&posts=4&start=1

 

[TightlineT]

wrechin2 - 2/3/2011 10:29 PM

I have seen those have broken/cracked oil lines and causing the fuel pump to have issues. The simplest thing will be to do a leakage test on it to determine the health of the engine. I will let you use one of my leakage testers (pick up at Crown Dodge) if you have access to compressed air or you can take a road trip tp "DUNVegas" and I can do one for you real quick. Don't trust a compression test. Here is why....

http://www.chattanoogafishingforum.com/forums/thread-view.asp?tid=50110&posts=4&start=1

You don't know me from Adam, but I'd say trust Wrechin2. That's all I got to say about that, other than I hope you are up and running soon....Jim

 

[craazyboutbass]

I might have some serious issues going on here. One of my friends might have a leakage tester... If it's something wrong with the piston, I'll end up taking it to someone for sure. Thank you James for the help, if you didn't have you're new job I would probably just bring it to you LOL. We'll get her running sooner or later. I am no good with this stuff, will just probably end up taking it to someone. Have a few guys here in Cleveland that might be able to help. I will keep y'all updated!

 

[wrechin2]

No problem. I always do mine at about 1/2" (.500)past top dead center and use a pair of vice grips on the flywheel to keep it from moving. Doing it at top dead will sometimes give you a false reading.

 

[craazyboutbass]

Well heres an update. One of my buddies from Parksville came over and we looked into it. Me not being an expert with motors of anykind missed a major flaw. The water hose that pees water out of the motor was cracked, therefore water was flooding the engine. We fixed that easily and wiped the engine dry. Did a compression test (not leakage) everything went just fine with that test. Looked into the carbs... they were clean. Found the cable that gives the motor gas when you apply pressure to the hotfoot, it was loose to where you couldn't get the motor wide open at all. Adjusted it correctly. Will take the boat up there tomorrow and see how she runs, hopefully she'll run good and we can get some fishing done. We think the water was getting in the carbs and like I said, when you trim the motor down you would get more power.... the water would be pushed away from the carbs when you trim down. I hope we got it fixed! Thanks to Rob for coming out and helping me this evening! Will let y'all know how she runs tomorrow.

 

[Skeeter]

Good deal Kevin.

 

[Skeeter]

Good deal Kevin. If that fixes your problem you got REAL lucky. This is what happened when mine sucked water in through the carb in December.

 

[craazyboutbass]

That is just awful right there! I hope I dont end up with that issue. All water is out of the engine now. We did hook the hose up and cranked the motor, she ran pretty good. But will see how she runs through the water tomorrow. Wish us luck!

 

[wrechin2]

Just let us know!