Bad Compression

[swick]

Just bought a 1999 120 hp Force. Compression test was 150 on 3 and 70 on the last. The engine is ultra clean, no signs of overheating, no paint chipped off, no gunk anywhere, no water in the oil. The prop has a pretty tore up blade on it, looks like the previous owner hit a boulder. Any suggestions or idea? I'm new at this so not sure what I got myself into yet. Thanks.

Oh yeah, the motor sat for at least a year and a half before it was run last and the owner said it worked fine (he had no reason to lie he told that to the repo man). I syphoned out most of the gas, could it be just build up or something simple? Can I put new fuel in it and get lucky?

 

[sho3boater]

Re: Bad Compression

Does not sound good. I would look in there at the walls for scoring, especially the exhaust side. Check the plug for metal particles. You can try to loosen carboned rings with seafoam or something, that sounds low for stuck rings but who knows.

 

[john from md]

Re: Bad Compression

Before taking anything apart, read the FAQ in the front of the maintenance forums and look for the Decarbing procedure. Do the process a couple of times, leaving it sit in the engine overnight if possible. After that, check your compression again.

Also, look at the thread called Waking up a sleeping engine in the same FAQ as your engine has sat a while.

John

 

[swick]

Re: Bad Compression

Okay so my problems are much worse. The compression initially read 150, 150, 150, & 80 (I know I said 70 before, I read it wrong).

I syphoned out most of the bad gas. I added 5 gallons of new fuel 50:1. Also added a bottle of Sea Foam to the fuel. Sprayed a little lubricant into the bad cylinder. The compression test hadn't changed at all.

My neighbor suggested to try and start it anyway. We put the muffs on, charged the battery up and gave it a few tries before we got it started. A friend suggested that we spray silicone spray into the carb while it was running, and we did.It sounded great but just a slight drip of water was coming out of the pee hole. We ran it for less then 45 seconds, Mike said there wasn't enough water coming out so I should shut it off.

Shut is off, took the muffs off, and now it won't do anything at all . It won't even crank. Now I can't even compression test it. Is it possible that its just a relay or fuse somewhere? Or maybe the engine rattled a conection loose? When I turn the key you can hear a click coming from the engine, thats it, nothing more. Did I sieze it up? Obviously we need a new water pump. I am so upset with the whole thing right now. I've been calling myself an idiot for a few hours and its not a fun time. I need to get a manual for this engine, the serial number is OE 359472

 

[john from md]

Re: Bad Compression

Yes you need an engine but, while you are waiting, we have years of good information right here at your finger tips.

Clicking from a solinoid is an indication of one of several things. Low battery, bad cables, corrosion at the battery terminals, corrosion at the ground points or bad solinoid.

When troubleshooting, you must always start from a known base line. the reason for this is that most people buy used boats and have no idea when parts were changed or what maintenance was performed.

A known base line for your starting system means, you know the condition and age of your battery (buy a new one if you don't), you have checked and cleaned the ground connections and you have cleaned the battery connections.

After you do those few items, turn switch to start and see if starter turns. Let us know.

Don't worry about the water pump as you need to change it so you have a base line for your cooling system. While you are at it, change the fuel pump diaphram for the same reason.

John

 

[swick]

Re: Bad Compression

Thanks John. Thats exactly the pep talk I needed. I'm frustrated cause I know my way around a car engine and nothing about outboards. I didn't think about the starter being a problem simply because it took us a little doing but we got it started, ever so short, but immediatley after we had nothing. I automatically assumed we damaged it worse. I need to find a good manual for this thing and get to it. Thats part of my problem, I know I can probably fix it (if its nothing too serious) but don't have the knowledge or manual yet. I've read reviews about the Seloc manual for this engine and people complained not enough pics, too dark, hard to understand etc. I know what auto water pumps look like, I haven't examined this thing very well yet. Is there another manual that may be better than Seloc? Thanks again.

 

[chitownborn]

Re: Bad Compression

clymers is really good, i have seloc and clymers, clymers is way better

 

[swick]

Re: Bad Compression

Yeah I was just looing at clymers online. I'll probably invest in one. I just bought a bootleg Seloc Cd version on ebay for $5. He didn't say it was a bootleg but I'm sure it is. Ah but its a start, I guess I'm officially a boat owner cause I spent more money than I wanted to and haven't had any fun yet.

 

[chitownborn]

Re: Bad Compression

i bought mine from doug russel marine and had it three days, clymers has clear pics and really detailed schematics and a hell of alot more specs than selco

 

[sho3boater]

Re: Bad Compression

Starting system is same as a car with a solenoid and starter, the only strange difference is OBs ground the ignition to run at the key...so a normal key switch will not work. Sounds like you have a bad battery connection/starter cable/starter/solenoid/neutral gear safety switch is off or something like that. They don't start in gear that is the safety switch, check that first.

The water pump you pull the lower unit and its on the big shaft. If you can get the muffs to seal tight and pressure the water in then it should take water even with a bad impeller in the pump. Right, don't run it very long with no water. Note it will trash the impeller to run it dry no matter what, you can only do that for a short time right after you take it out of the water and its still wet and don't run it long at all. With most motors if you get pressure on the water in the muffs leave it sit on for 5-10 minutes and water will actually start to come out of the exhaust once the motor is full. That is the true safe way to wet start them, but there may be times that will not work. I try to do that in the spring for the first fire up when I know it is dry inside. Note it may take 30sec or so to get water out of the indicator hole even in a lake.

 

[swick]

Re: Bad Compression

One problem is that the starter is toast. I came home today and popped the hood off in the daylight. The wire going from the solenoid to the starter was all but melted and I couldn't get the starer to do anything. The solenoid still clicks so I assume that is fine. The solenoid is seperate from the starter, not connected or attached to each other in anyway (other than the wire of course). So I now have my starting point. My wife called a local outboard mechanic who said he will borescope the cylinders and inspect for $25, so I'll have him do that on monday, before I go and buy a new starter. I have the feeling everything is going to be alright, but I'll let you know. Any other advice or pointers are plenty welcome. Thanks.

 

[swick]

Re: Bad Compression

By the way where can I buy a new starter besides online? Is there like an advanced auto for boats?

 

[john from md]

Re: Bad Compression

Any place you go other than on line and you will pay through the nose. There is a guy called 14rebuilders who sells on ebay. He has a facility in either ohio or west virginia. He is the cheapest price and you can probably have him ship it in a hurry too.

John

 

[Rope Goat]

Re: Bad Compression

Just wanted to give you my two cents worth on buying a starter online. I got one off E-Bay (from a reputable seller w/ lots of + feedback). It worked for about literally 20 - 25 starts before it stopped working. I ran through alot of unneccessary diagnostics before realizing it was just a poorly manufactured starter (made in China). Got another new one from the local marine mechanic (MERCURY Quicksilver manufactured in Wisconsin), paid 3x what I did online, but starts up like a champ EVERY time now. Maybe I just got unlucky with that cheapie starter, after all $90 is alot better than $299 + tax, but no headaches now. Again, just my .02!
Good luck with your other issues, I've had my Force 120 for 3 1/2 years now and you'll never find better advice (FREE!) than you will on this site.

 

[swick]

Re: Bad Compression

Rope Goat did you buy from 14Rebuilders on ebay? They've got 99.9% feedback and offer a 1 year warranty on the starter, but their starter is made in china, I did email them with questions.

 

[swick]

Re: Bad Compression

so the "local mechanic" that I went to turned out to just be some scam artist, needless to say I didn't leave my boat with him. Anyhow I'm back to the starting point, literally. I need a starter, I know I can buy one off 14Rebuilders on ebay for $72 + shipping. He gives a 1 year warranty so thats comforting, although not sure what the return policy is yet, hopefully won't need to.

I still however have not forgotten the original problem of bad compression. 150 X 3 and 80 on the lowest cylinder (bottom one). John suggests I do a decarb, could that be the cause of such low compression? Also could be a stuck ring, but that is almost half the compression as the other 3?

Does anyone think that I should forego buying a new starter and doing the decarb and just pull the head off? I am totally up for suggestions.

 

[swick]

Re: Bad Compression

Good news.... I put on the new starter (bought from 14rebuilders afterall). A few days ago I put a little Marvel Mystery Oil into the bad cylinder and today the new compression test went up to 95 on the bad cylinder. I started the motor for a few minutes and shut it off. Added some more mystery oil, started it again, and like magic the compression went up to 110. Now its within 40 of the others. From 80 to 110 is a huge difference though. I'm going to let that mystery oil set in again and see if it gets up anymore in the next couple days.

Only other problem is that I'm not getting any water out of the tell. I had the LU sitting in a tub of water and hosed everything down real good first. I took off the L/U the other day and inspected the impeller, looked practically brand new so I put it back on figuring it was fine. While I had the L/U off I also ran the hose water through the system and watched it come out of the tell. What else could it be?

 

[john from md]

Re: Bad Compression

It takes about a minute to get through the head and out through the tell tale. Start it without the cowl on and put your hand on the exhaust plate. It will start to warm up but then will cool down once the water gets into it. If it gets too hot, it is not getting water.

John

 

[swick]

Re: Bad Compression

Thanks John, I prbably didn't run it long enough. This engine hasn't been run in at least a year and a half before it came to me and I'm doing alot of learning.

 

[john from md]

Re: Bad Compression

If you don't know by now, your engine is starting lean. Are you pushing in the choke? Do you have the trottle in fast idle? The reason I ask about the fast idle is that it was not idling as fast as it should when on fast idle.

As soon as it runs on its own, you should do a complete decarb. That will free up your rings and clean up any residual varnish in the fuel path. When you decarb it, I suggest you let it sit for overnight on the third relay. After that, take it out for a good run and you will blow all the carbon out of the cylinders.

BTW, engaging the prop in a bucket makes for a real mess? And I could tell that your dog thought that bucket of water was for her.

John