Merc 175 bogging

[JakeMore]

I run a Merc. 175 in a 19' Nitro. I took my boat out this morning for the first time in a month. The last time I took it out I ran it trying to run some old treated gas(pri-g) through the carbs. It ran fine. Got up on pad, But it did take about 10-15 cranks with the key to start.Well, this morning ,cranked it right up in the driveway on the second try. Got the boat in the lake, and on the first crank it started right up, great right ? Until I put it in gear and it stalled. After about 30 cranks(and the battery very low it started, and stalled etc. This went on for 5 minutes until it breathed life and I hammered it to a speed of about 10mph. I ran about a 1/4 mile like this, when the boat came to life and got up on pad. That lasted awhile(about 1/4 mile),when I tried to slow down , and stalled. It cranked right up but would only get up to about 5- 10 mph.I did notice that the fuel bulb was soft in between stalls. Im not much of a mechanic So I didnt really know where to start troubleshooting. Thanks for the help. I dont think I can take the disappointing look from my 6 yr. old that had the fishing fever this morning.( never got a line wet).

 

[KCLOST]

Re: Merc 175 bogging

A soft fuel bulb after a stall is relative... A more obvious fuel starvation problem is whether or not it went flat just before the stall....<br /><br />Anyway....<br />Check the spark on all cylinders. and the compression... This is the easiest way to start at this point....<br /><br />After you got the engine running, did it idle normally or was it rough, different?<br /><br />We need the year and serial number for the outboard also, this will help us...<br /><br />If you are sure that it is a fuel starvation problem. You can check the fuel filter within the tank and on the motor also. But we need more info to confirm that is the reason for your problem.

 

[JakeMore]

Re: Merc 175 bogging

this probably sounds stupid ,but, where do I find the Serial Number and year ? Sorry....

 

[rickdb1boat]

Re: Merc 175 bogging

Look on the transom bracket for a plate with the numbers or they may be stamped into it. Find that and we will provide the year. Need serial number, so post whatever you find.

 

[rickdb1boat]

Re: Merc 175 bogging

Sounds like the old fuel may be the problem, plus a clogged fuel tank vent. Try running on a portable 6 Gallon ( pre-mixed at 50:1 if you have oil injection) tank with fresh fuel and see how it goes. don't forget to open the portable tank vent. Could also be bad primer bulb or pick-up in the fuel tank is clogged with gunk. Try the portable out and see how it goes. Change the spark plugs before you do this..

 

[JakeMore]

Re: Merc 175 bogging

the number stamped on the transom is #BUJ73507B494. And it is oil injected.

 

[JakeMore]

Re: Merc 175 bogging

also, its a 1994. It seems to be idleing normally when it got warmed up. It was still stalling at times when put in gear.

 

[KCLOST]

Re: Merc 175 bogging

That sounds like the sn# for your boat, not the motor....<br />Have you registered the boat and motor before? If so it is probably in the registration form/receipt. (might be a quick way to find it). <br />Rick is talking about the bracket that mounts the motor to the transom or jack plate if you have one. Not the actual transom itself...<br /><br />If it idled normally, it does sound like a starvation problem, not electrical. Check everything rick mentioned.<br /><br />Let us know...

 

[JakeMore]

Re: Merc 175 bogging

found it #0G016390. And its a '94. Sorry about that

 

[JoeW]

Re: Merc 175 bogging

Also, check your fuel line for hairline cracks. I once had a hairline crack on the hull side of the line which caused the same symptoms.

 

[JakeMore]

Re: Merc 175 bogging

what are the specs on the spark plugs (gaps). What kind do you recommend ? Im gonna try the portable gas tank and go from there ? Unless there are any more ideas.Question here, Would a undersized fuel line to a carburator cause problems ? Before this trip I changed a line that was leaking my last trip, that might have been a hair smaller than the original.

 

[outboardguy]

Re: Merc 175 bogging

Nitro, The recommended plugs for the engine are NGK BU8H or NGK BUZ8H if you want a resistor plug.These plugs are surface gap and do not have an adjustment.I would think that your fuel line should be at least 3/8 ID.So if your replacement line is smaller that may be a problem.For some reason I think you may have water in the fuel or just bad fuel.The portable tank will eliminate the bad fuel but you may still have problems if the carbs have water in them. You may try and get a clear plastic container(Gatorade Bottle) and remove the fuel line end from the engine side of the fuel line.Now using your primer bulb pump some fuel into your container.If there is water it will be evident at the bottom of the bottle,If the fuel is bad you should be able to smell it and tell.

 

[JakeMore]

Re: Merc 175 bogging

I am gonna try that. The line Im talking about is in the motor, its a line that goes to a carburater. Question: Why would it start out of the water just fine ?<br />

 

[JakeMore]

Re: Merc 175 bogging

When Rick talked about a clogged fuel tank vent, is he talking about the vents on the opposite side of the boat that the gas goes into ? I have 2 one for the main tank and one for the auxillary. What do I do to check them. They used to have threaded caps on them , but the kids got to them.

 

[rickdb1boat]

Re: Merc 175 bogging

These are air vents that let air in the fuel tank. Not where you fill the tanks with gas. They are small lines(5/8" or so). Otherwise it creates a vacuum in the fuel tank and starves the engine of fuel. In Texas, the mud dobbers love to nest in them and clog them up, especially if the caps are missing.. Blow compressed air through them(If you have 2) and see if they are clear. I would still try the portable tank and new fuel line and bulb, as it will eliminate several causes of the problem immediatly. Let us know...

 

[KCLOST]

Re: Merc 175 bogging

Remove the air vent line at the tank(s) and blow from that end, don't blow into the tank...See if its free of debri.<br /><br />Also did you try running the engine from the auxillary. If so, did you see any difference?

 

[JakeMore]

Re: Merc 175 bogging

hello poeple, I know its been a while since my last post, but had some knee problems Ive had to deal with. So basically Im just getting to those suggestions. First of all tried to pump gas with the quick connection to the motor using the bulb. no luck . I need the female part of the connector for that to work(quick connect needs to be engaged). Checked for clogged fuel vent lines(built in screen on vents). Thats good. My new problem is this.......I tried to start the motor, any after quite a few cranks, and puffs(smoke rings) coming from the prop, it cranked up with white smoke coming from the same place (back of prop). When I saw this I cut it off. Thanks for the help !

 

[JakeMore]

Re: Merc 175 bogging

Im getting ready to go buy the portable tank to make sure that its a gas problem. My motor is oil injected. What do I do with the portable 6 gallon tank as far as fuel ? Straight gas or a mix ? <br />

 

[JakeMore]

Re: Merc 175 bogging

Ok, Ive checked the gas, and there are black particles in the gas ??? I have about 10-15 gallons of gas left in the tank. What next ? I couldnt see any sign of water. Thanks

 

[outboardguy]

Re: Merc 175 bogging

Generally black particles means that your fuel lines are rotting from the inside due to the age of fuel and the amount of alcohol in today's fuel.You are probably going to have to rebuild the entire fuel system.New fuel lines tank to engine and engine to carbs,fuel pump rebuild,carbs overhauled.You will be amazed at what the inside of the fuel line looks like.