Merc 175 ????

[mas942]

I have a 1991 175 black max that ran perfect.

Took it out yesterday ran it a wot was runn ing fine than it stopped suddenly.Checked every thing started,ran fine than stopped again.Pulled the cowl no oil in reservior on motor and the alarm never went off, found the resevior tank was unhooked.Rehooked it ,filled tank on motor, started same thing again .

Think I toasted something?

Going to do compression ck any other things to look at hoping for the best.

Thanks Mike

 

[WillyBWright]

Re: Merc 175 ????

Long as you're at it, check your gearlube. A siezed gearcase will lock up a powerhead too. But I'm afraid that empty oil tank is the smoking gun here. Check your compression, but you'll probably know as soon as you see what's on the sparkplugs.

 

[mas942]

Re: Merc 175 ????

Thanks for the reply,I assume I'm looking for gray color with metal or other ugly stuff on the plugs.The gear lube was just changed and was ok.

Not having rebuild an outboard, but having done a number of auto motors top to bottom.How much differance is there? Special tools? I'm thinking of taking a shot at it #1 to save some bucks{I'm planning on repowering next season} and # 2 I'm in New Jersey on the coast and the chances of a merc tech getting it done in the near future is slim to none.

Any Help on rebuild manuals and kits. As you can tell I'm not overly optimistic on the chances of nothing being wrong with the power head.It has 650 hrs on it and the only major/minor thing done as far as I can tell was a stator a few years ago.

Thanks Mike

PS motors worth 1500 to 1800 by what I can tell is it worth it to rebuild it?

 

[Bob_VT]

Re: Merc 175 ????

Think back..... in it's last few minutes of so of running .... did it seem to run faster or stronger? Hopefully it only took a single piston.

 

[mas942]

Re: Merc 175 ????

No it was running strong and I thought I actualy had wrapped a crap pot line it stopped that quick.

It'll start right now and it idles rough ,It'll come up on plane and just bog down and just stop running at first I thought it was a lower end but like willy said the oil res looks like a smoking gun.

 

[CharlieB]

Re: Merc 175 ????

Smoking gun or not, do the tests and see, post the results,
What is compression on each cylinder
What do the plugs look like
What does spark look like
Do you have a DVA Meter
What is the stator output on the ignition leads, charging leads
What is the trigger output
Water pressure/flow
If everything passes then run it again and when it stops immediately test the spark/ignition components

I've seen faulty ignition modules that shut off once up to temp under load but would idle all day.

NEVER ASSUME ANYTHING
Test until you prove a fault

 

[mas942]

Re: Merc 175 ????

Thanks for the imput I will run the test and get back to the forum with results Thanks again Mike

 

[mas942]

Re: Merc 175 ????

Ok found the problem, Looking at the motor from the rear ,motor warm ,left bank ,Port, top to bottom 125 lbs,131 lbs 127lbs all light carbon deposits plugs ok

Right bank Starboard top to bottom 123lbs,127 lbs light carbon plugs ok.

Bottom right bank cyl starboard "zero" lb ,plug ugly with metal deposits...I'll guess,looks like hole in piston also alarm never sounded so the alarm or wiring must be bad..Next Step???

Thanks Mike

PS Stator was replaced last season with new batteries,water flow good and pressure good, the pump/impeller was replaced last season.

Also ser # is 06619969 175 black max I beleave its an 85' merc site lists it as 76-88 the boat is an 85 Grady White Seafarer .Assuming I have to replace a piston what parts do I need from iboats.com ?

 

[Bob_VT]

Re: Merc 175 ????

Well it can be re-sleaved and a single piston can be installed provided the crank is okay.... ahh the beauty of a 2 stroke.

 

[mas942]

Re: Merc 175 ????

Back to the top of the thread.

Can this be done with the motor still hung on the boat.

I'm going to pick up a Seloc repair manuel.And attemp it myself any suggestions as to a step by step.

What needs to come off the motor and can the piston be pulled from the top or does the power head need to be pulled.

We have a tournament in three weeks and I would like to make it.Tech say they can even think about it for 2 weeks.

Help!!! Mike :redface:

 

[mas942]

Re: Merc 175 ????

Well I found some time to work on the boat.

Its out of the water I pulled the heads and found a hole in the lower edge of the starboard lower piston looks like the ring snapped.One small groove in the cylinder wall and some debris attached to the wall where the hole is.

All else looks good. Can it be honed or do I need to pull the power head and have it re-sleeved? And is it worth it?

Thanks for you help, Mike Sr

 

[Chris1956]

Re: Merc 175 ????

It is beyond the hone stage. if it has a cast iron sleeve, you can have it rebored and install an oversize piston and rings. You will need to pull the powerhead, strip it down to just the block and take it to a machine shop!

 

[dompie99]

Re: Merc 175 ????

Hi,

in the near future, dont i say DON'T rely on any gimmicks that sets the oiling parameters on your engine,

Mix the Oil directly in the fuel cell in a 50:1 ratio or smaller and that,s IT...

remove the pump links, pump, make an aluminium plate that match the hole and ohh i forgot, remote the shaft that drives the pump also, and plug the dammm hole

Next time, you wont forget, and the pump will rest in a garage away from any disturbing behaviors..

 

[mas942]

Re: Merc 175 ????

Thanks I'll pull it apart and give an update. While its apart what else should be replaced? don't want to dump alot of $ in it because of the age.

 

[studlymandingo]

Re: Merc 175 ????

Hi,

in the near future, dont i say DON'T rely on any gimmicks that sets the oiling parameters on your engine,

Mix the Oil directly in the fuel cell in a 50:1 ratio or smaller and that,s IT...

remove the pump links, pump, make an aluminium plate that match the hole and ohh i forgot, remote the shaft that drives the pump also, and plug the dammm hole

Next time, you wont forget, and the pump will rest in a garage away from any disturbing behaviors..

Ahh... another automatic oiling naysayer.

If your oil pump works, there is no reason not to use it. While the motor is apart, you could replace the oil pump drive gear if you like. The automatic oiling on these motors is not the death sentence that some think; it's actually a really good system.​

 

[studlymandingo]

Re: Merc 175 ????

I don't want to dump alot of $ in it because of the age.

A '91.... Heck that thing is still a pup!!! Get the piston fixed and run her for another 15-20 years!!!​

 

[mas942]

Re: Merc 175 ????

Thanks, I think I will fix it, as far as the oil system it worked fine the buzzer didn't go off because of a bad wire.Thems the brakes....

Should I re-ring the motor when its apart???Anything else while I'm at it???

Need some other parts like a tilt ram seal kit and and new bushings in the steering mount.Wheres the best place for new and used parts for this motor.

 

[mas942]

Re: Merc 175 ????

Houston, I think we have a problem !!!

I'm reading the Seloc manual and it says the 175 with a serial # 6618751 and above is a chrome plated cylinder bore. My is 6619969.

The number 5 is the piston that failed, and has a groove in it you can feel with your finger nail, all else on the motor is ok.I'm going to ck it with muratic acid to see if it went through the chrome to the aluminum.If it is not through, can it be saved as it says it can not be honed or bored????

 

[studlymandingo]

Re: Merc 175 ????

If you find it has gone too far, you can always get a new sleeve.​

 

[j_martin]

Re: Merc 175 ????

Thanks, I think I will fix it, as far as the oil system it worked fine the buzzer didn't go off because of a bad wire.Thems the brakes....

When you turn the key on, it should go beeeep, beep, beep, beep. That says "The oil warning system is a go, including the wire."

You don't know what you don't know. Now you know.

Fix it and go enjoy some boating.

John