Mercruiser 3.0L

[ramelton35]

I just purchased my first boat and it is a 2004 SR 180 BR with a Mercruiser 3.0L. I have had the boat out several times now and the problems seem to get worse.

First off it is getting more and more difficult to start. The last time I was out it took a long time to get it to turn over and when it did it just died. After a little while I got it to turn over and run. About a 15 min. later I turned the ignition off and it backfired about 5 or 6 times. I turned it off a little while after that and it backfired once. The boat runs good and has no trouble accelerating. Any ideas on the ignition and backfiring?

Also my speedometer stopped working last time I was out. Does a hose or something just need to be blown out? Where is that located?

I was also told by a guy that my bellows on my lower unit were stretched out and should be replaced. He said that if they weren't replaced they could be quite expensive to fix. Not knowing much about boating I had no idea what he is talking about. Is there an advantage to fixing these before they go bad? What happens if they do go bad? He also said that something needs to be trimmed and doesn't look like it can be trimmed anymore. Is he talking about the lower unit trim?

Please help a new boater out, Thanks!

 

[K9Deuce]

Re: Mercruiser 3.0L

Back firing is usually a ignition/timing problem. The backfire is either an exhaust valve opening when the cylinder is firing ( backfire thru exhaust) or the intake valve is opening when a cylinder is firing ( backfire thru air intake). Is the igntion distributor loose? the igntion cap loose? has anyone performed any recent work? With out seeing the boat its a little hard to say. I would suggest you take it to a good boat mechanic.

As for the bellows you want those replaced if they are in need of replacement. Bellows can cause at the least a water leak into the boat wich isnt good. That water leak can cause some severe problems. A u-joint bellow that is bad will fill the boat with water and can damage your u-joints, gimble bearing and the engine coupler is it is not fixed. I would not use the boat until they are inspected and replaced.

 

[metro3pilot]

Re: Mercruiser 3.0L

Not sure if this will help or not

I have an 02 merc 3.0 and it will run on, and diesel if I shut it down immediately after I have been running it awhile ....if I let it idle awhile before I turn it off, it seems to take care of that problem...

mine also took awhile to figure out it's sweet spot on the throttle for starting, it's pretty easy to flood it out, or to starve it of fuel ... and I have been known to crank it for awhile to get it to run.

If your bellows is bad it can sink your boat, may want to replace them or have a mechanic do it, it's not all that expensive and the alternative is replacing the boat when it sinks, so it's much cheaper to replace the bellows

as far as the speedo goes you should have a small hose that goes into your outdrive on the backside of the outdrive towards the middle of it with a quick disconnect hose, you might have some material that has plugged it ... disconnect the hose and blow air from the disconnect into the outdrive, never blow into to the hose towards the speedo or you might be buying a new speedometer... if that don't work disconnect the hose at the back of the speedo and blow the air towards the outdrive. If it's not in the outdrive there will be a plastic thing attached to your transom with a hose coming out of it , look for an obstruction and clear it.

not sure what he's talking about as far as trim goes.

I am not a mechanic so take the advice for what it's worth and have fun boating

 

[ramelton35]

Re: Mercruiser 3.0L

As for the bellows you want those replaced if they are in need of replacement. Bellows can cause at the least a water leak into the boat wich isnt good. That water leak can cause some severe problems. A u-joint bellow that is bad will fill the boat with water and can damage your u-joints, gimble bearing and the engine coupler is it is not fixed. I would not use the boat until they are inspected and replaced.

Well in all the times I have had it out I have not seen water in the engine compartment. I turn the bilge on quite frequently to check for water and it only has pumped once. I believe that was from rain water. If the boat isn't leaking though should I be concerned about the bellows? What is the indicator that they are bad, leaking water into boat?

 

[ramelton35]

Re: Mercruiser 3.0L

mine also took awhile to figure out it's sweet spot on the throttle for starting, it's pretty easy to flood it out, or to starve it of fuel ... and I have been known to crank it for awhile to get it to run.

as far as the speedo goes you should have a small hose that goes into your outdrive on the backside of the outdrive towards the middle of it with a quick disconnect hose, you might have some material that has plugged it ... disconnect the hose and blow air from the disconnect into the outdrive, never blow into to the hose towards the speedo or you might be buying a new speedometer... if that don't work disconnect the hose at the back of the speedo and blow the air towards the outdrive. If it's not in the outdrive there will be a plastic thing attached to your transom with a hose coming out of it , look for an obstruction and clear it.

not sure what he's talking about as far as trim goes.

I am not a mechanic so take the advice for what it's worth and have fun boating

So when starting should I have the throttle somewhat forward while keeping it in neutral? Not locked straight up at down?

I will have to take a look at the speedo hoses.

Thanks for the help

 

[BeaufortTJustice]

Re: Mercruiser 3.0L

Pertaining to the u-joint bellows...when they fail, you may win murphy's lottery and have it fail slowly and in a small area...but otherwise if you have my luck, you will be in the middle of a lake and it will fail quickly and completely, in which case I hope your bilge pump is up to the task. Do yourself a favor and replace it, then make it a routine part of your preventative maintenance checklist. They are rubber and eventually fail due to age alone.

 

[BeaufortTJustice]

Re: Mercruiser 3.0L

I have an 02 merc 3.0 and it will run on, and diesel if I shut it down immediately after I have been running it awhile ....if I let it idle awhile before I turn it off, it seems to take care of that problem...

I had the same issue with my 07 VP 3.0L...started using a higher octane fuel and that has cured it...regardless, it is always a good idea to let it idle a while after a hard or long run.

 

[ramelton35]

Re: Mercruiser 3.0L

Pertaining to the u-joint bellows...when they fail, you may win murphy's lottery and have it fail slowly and in a small area...but otherwise if you have my luck, you will be in the middle of a lake and it will fail quickly and completely, in which case I hope your bilge pump is up to the task. Do yourself a favor and replace it, then make it a routine part of your preventative maintenance checklist. They are rubber and eventually fail due to age alone.

Should the bilge be running constantly when the out on the water? Or run it when the blower is running?

Could the backfiring be from poor fuel quality? What are you guys running in your boats? I have been putting in 89 oct, but this has ethanol in it. The regular at the station I go to is 87 oct, but is ethanol free, or should I put the premium in it?

 

[BeaufortTJustice]

Re: Mercruiser 3.0L

If you have a strictly manual (only way to pump is by toggle switch) bilge pump, then I would make it habit to hit the switch and look back to see if any water pumps out every so often...

Most pumps are automatic, however, in one of two ways...you may want to check to see which you have. One uses a float switch to turn on when water reaches the float...the other turns on by itself every 2-5 minutes and if it senses resistance (water to pump) it will continue pumping until no more resistance.

Yours being a 2004, I would think that you have an automatic type...but you never know until you know.

 

[Rocky_Road]

Re: Mercruiser 3.0L

I just purchased my first boat and it is a 2004 SR 180 BR with a Mercruiser 3.0L. I have had the boat out several times now and the problems seem to get worse.

First off it is getting more and more difficult to start. The last time I was out it took a long time to get it to turn over and when it did it just died. After a little while I got it to turn over and run. About a 15 min. later I turned the ignition off and it backfired about 5 or 6 times. I turned it off a little while after that and it backfired once. The boat runs good and has no trouble accelerating. Any ideas on the ignition and backfiring?

Also my speedometer stopped working last time I was out. Does a hose or something just need to be blown out? Where is that located?

I was also told by a guy that my bellows on my lower unit were stretched out and should be replaced. He said that if they weren't replaced they could be quite expensive to fix. Not knowing much about boating I had no idea what he is talking about. Is there an advantage to fixing these before they go bad? What happens if they do go bad? He also said that something needs to be trimmed and doesn't look like it can be trimmed anymore. Is he talking about the lower unit trim?

Please help a new boater out, Thanks!

You should have the Alpha Gen II drive, and the water pickup for the speedo is a tiny hole on the leading edge of the lower unit. It is not unusual for this to pick up some trash, and the solution is to take a drill bit slightly smaller...and to hand turn it inside this pickup hole.

As for your bellows: Mercruiser says that their O.E.M. parts are good for 5 years...and you are getting there. The larger, lower, bellows is your exhaust and you can actually run safely with it totally missing. This lower bellow will not sink you, regardless of it's condition.

The upper (u-joint, or drive) bellows is just the opposite...if it is torn you will get water into the driveshaft and u-joint area, and at best will simply destroy your u-joints and gimbal bearing. At worst, you can sink your boat. Since it only takes the removal of a half dozen nuts to inspect all of your bellows, I would recommend that you have a trusted mechanic do this much. Not all 5 year old bellows needs replacement, but should be inspected....

As to your backfiring...too few mechanics know how to properly set the base timing on your 3.0L, and you may be the victim of someone that didn't know the proper procedure. Once again...find someone that knows this engine, and have the timing, and carb settings, checked.

Happy boating!

 

[Searay87]

Re: Mercruiser 3.0L

re: Hard to start

The routine I use for my 3.0L merc is to push the throttle fully forward three times. Then depress the throttle only button then push it forward to the 10 o'clock position and start the engine. Works every time.

 

[PBJMAN]

Re: Mercruiser 3.0L

Checking your bellows is easy if you know what they are. They are the corrugated rubber tubes that you can see between the boat and the outrive when it is tilted up (or "trimmed up"). They are thick black rubber and should be firm and pliable. If they are showing signs of cracks or dry-rot, you need to have them replaced. The bottom one is the exhaust bellow and probably has slits or gaps in the folds, that is ok, it came that way. The upper one is the one that everyone is cautioning you about, it must remain sealed to keep the water out of your driveshaft, gimble bearing, and out of your boat!

 

[BUZZZMEA]

Re: Mercruiser 3.0L

re: Hard to start

The routine I use for my 3.0L merc is to push the throttle fully forward three times. Then depress the throttle only button then push it forward to the 10 o'clock position and start the engine. Works every time.

I recently had to replace the fuel pump and rebuild my Carb because apparently the ethanol being used in the gas these days degrades the pumice bowl filter inside the fuel pump bowl and lets some of that gunk and sediment clog up the jets in the carb Despite the small micron filter on the carberator (at the fuel line inet of the carb). mine would start, but would starve out when the throttle was pushed. Then it was almost a miracle to get her started again. I have been told buy 5 different Sea Ray and Mercruiser Mechanics that it is not an "if" but "when" this will happen to an an older model mercruiser (my Sea Ray 175 is a 1997).

 

[iamneo_]

Re: Mercruiser 3.0L

my 85 sunrunner has a 3.0, I noted the choke hanging up on its first sea trials with me. Makes it hard to start, and continue running. Since I fixed it, the goofy engine starts almost without making one full revolution. I set mine to 2 deg lean. I also run no less than 89 octane. Make sure you have power to the choke for the pull off when it warms up. I only have to move my throttle lever once forward when I start it.

 

[DayCruiser]

Re: Mercruiser 3.0L

re: Hard to start

The routine I use for my 3.0L merc is to push the throttle fully forward three times. Then depress the throttle only button then push it forward to the 10 o'clock position and start the engine. Works every time.

I recently had to replace the fuel pump and rebuild my Carb because apparently the ethanol being used in the gas these days degrades the pumice bowl filter inside the fuel pump bowl and lets some of that gunk and sediment clog up the jets in the carb Despite the small micron filter on the carberator (at the fuel line inet of the carb). mine would start, but would starve out when the throttle was pushed. Then it was almost a miracle to get her started again. I have been told buy 5 different Sea Ray and Mercruiser Mechanics that it is not an "if" but "when" this will happen to an an older model mercruiser (my Sea Ray 175 is a 1997).

I will have to give that 3 pumps a try. Interesting about the Ethanol. My old 3.0 will start easily when first leaving the dock but you really have to grind that starter to get it started when it is hot after a swim. Keep pumping the throttle. Very stressful even though it always starts. Carb was rebuilt 2 or 3 years ago. I use a inline water filter separator. I went to 93 octane last weekend and still had the problem this weekend. I am think about using Ethanol fuel treatment. That is the problem because when you throw Ethanol into the mix then it is very hard to narrow down the problem. Maybe we have to take out the fuel pump filter and rely on the fuel water filter separator?
To the thread starter. Get that Bellows repaired asap!! You risk the boat sinking

 

[Searay87]

Re: Mercruiser 3.0L

Just to clarify, the 3 pumps on the throttle is when the engine is cold. After it's warmed up I dperess he throttle only button and set it around the 10 o'clock position.

 

[ryanr623]

Re: Mercruiser 3.0L

Just to clarify, the 3 pumps on the throttle is when the engine is cold. After it's warmed up I dperess he throttle only button and set it around the 10 o'clock position.

This is correct. If your boat doesn't start like this, then something else is wrong. After my boat is warm, it takes just a flick of they key to get started, in neutral. It is a 1982 Mercruiser 120, but was totally rebuilt 4 years ago and maintained to a T.

OP try pumping the throttle as others have said, and while NOT in gear, put the throttle about 1/5 the way forward, and start. Should start right up.

 

[DayCruiser]

Re: Mercruiser 3.0L

Just to clarify, the 3 pumps on the throttle is when the engine is cold. After it's warmed up I dperess he throttle only button and set it around the 10 o'clock position.

Oh ok, I have tried that and still no go. While churning the starter and pumping then it started when I throttled back close to neutral. Seems like it is different every time. Just not a easy start.
Fires right up when it is cold with goosing it half way and then back close to neutral before trying to start.
I tried all the way down and back and then start. Half way down and then start. Neutral and then start. End up pump pump pump pump and then it starts. Maybe I will try and pump it a few times before trying to start. I was worried about flooding it.
Idles fine, runs fine. Easy start when cold. Thermostat reading is at 160 when idle. Between 140 and 150 when going forward. Maybe it is running too hot and effecting the Carb and Ethanol?

 

[ramelton35]

Re: Mercruiser 3.0L

re: Hard to start

The routine I use for my 3.0L merc is to push the throttle fully forward three times. Then depress the throttle only button then push it forward to the 10 o'clock position and start the engine. Works every time.

So you are basically shifting the boat into drive 3 times and then you press the throttle button and push to 10 and start it?

Does that button basically keep it in neutral and allows you to rev up the engine correct?

 

[ramelton35]

Re: Mercruiser 3.0L

re: Hard to start

The routine I use for my 3.0L merc is to push the throttle fully forward three times. Then depress the throttle only button then push it forward to the 10 o'clock position and start the engine. Works every time.

my 85 sunrunner has a 3.0, I noted the choke hanging up on its first sea trials with me. Makes it hard to start, and continue running. Since I fixed it, the goofy engine starts almost without making one full revolution. I set mine to 2 deg lean. I also run no less than 89 octane. Make sure you have power to the choke for the pull off when it warms up. I only have to move my throttle lever once forward when I start it.

I'm from the midwest so a lot of the fuel has ethanol in it. Are you guys running ethanol free stuff? The cheapest gas here is a 89 oct with 10% ethanol. The "regular" is 87 with no ethanol and then the premium at 91 oct. What would you guys recommend?