1989 Mercury Classic 50

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Flowie

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I have a Mercury classic 50 on a 15' Lowe angler. I am not the best mechanic, certainly not a good outboard mechanic. I have owned the boat/ motor for 5 years. I have fogged/ winterized faithfully..changed the oil. I use seafoam in the first and last tanks of fuel mix I run every year. This year I replaced the plugs.

A couple weeks ago when I left the launch on the river, I opened ip the throttle and about 200 yards away from the boat launch it bogged down, basically killed itself -and some smoke issued forth.

There was some oil on the the transom clamp and it looked like it was coming from the front of the powerhead.
When I got home I took the shroud off....sure enough it looked like oil/ fuel was coming from the carbs and I am due for a carb rebuild on both carbs.

The Shop ( which I have used before) wants 680.00 for parts and service on the dual carb rebuild. This seems a little high to me. Your thoughts?

I did look in the lower unit...I think the smoke was due to a bad waterpump. I replaced the waterpump ...my shop wanted 330.00 for that. For me , a mechanic of marginal skills at best , this took me an hour and about 75.00 worth of parts and materials. Has my boat mechanic become predatory in his billing practices? I have used him twice before and I didnt feel like they were gouging me.

Also...Any comments on the Classic 50. Anyone owned one and have an opinion or advice on them?
Mine is an 89 and has had the oil injector disabled.

Thanks in advance, I lurk here a bit but rarely post because I am not really much of an engine guy
 
The fact that the engine stopped on it's own after a few hundred yards and you experienced a water pump failure was what caught my attention. Secondly you said the engine bogged down and killed itself. By chance did it feel like something was putting the brakes on the flywheel and stopping the engine?
You did not mention a compression check and individual cylinder readings. Before doing anything get those figures. They are crucial. Also take a good look at the plugs and see if there is anything noticeably different on any of them.
Did you run the engine back to the ramp?
When you tried to restart the engine did the engine turn over just like normal the first time or did the starter seem like it was stuck? After a few minuted did the engine turn over and the engine eventually start? Did the engine idle ANY different than normal?
 
It went from WOT running fast...to a gradual degrading to basically idle...then finally killed itself.
I used the trolling motor back to the launch.
I did try to restart it at the launch. It reluctantly fired up.
It acted like it ran rich when it was idling. I only let it run a few seconds though...was scared of doing more harm to it.

Compression was 130 ish across all 4 cylinders.

I am for sure it needs a carb rebuild, and not just by my assessment and the boat shops assessment.
I have a really good relationship with the guy that takes care of my cars, lawn mowers and snowthrowers.
He is of the same opinion.
 
There aren't many things that will cause what you described.
Water in fuel will do it and your 200 yds would be about right for the water to hit. Pump some fuel into a clear container and see.
A weak fuel pump will do as you describe. You can diagnose simply by hand pumping the primer bulb while running at the RPM the issue occurs at. If it runs by hand pumping then you have found the issue.
Air in the fuel supply system. Again, hand pumping the primer bulb will overcome this and allow the engine to run normally while pumping.
As far as the carb rebuild goes......
The carbs have separate systems in them. They have a low speed or idle circuit, some have an intermediate or mid-range circuit, and they have a high speed circuit. The high speed circuit is the one you were running on but the 200yds distance does not fit. If you have a plugged HS circuit normally it is immediate. If it ran recently (previous trip) up to WOT then you can almost rule out the carbs. Keep in mind I am going by what you describe.
For a mechanic to automatically tell you that you need a carb rebuild? I would question it.
 
Water in fuel is unlikely, i just filled both tanks all the way to the top...fresh 6 gallons of gas, 16 oz quicksilver. The main tank was bone dry.
Reserve tank had about an inch of fuel.

I guess we will see if it was the carbs or not. It comes back from the shop sometime this week. :?


Thanks for the response and the ideas, you are always very helpful on this forum from what I have read in other threads.
 
Fuel and oil coming out of the carburetors indicates that air from the crank case is being pushed through the carburetors backwards when the pistons move up and down.

The reed valves are supposed to allow air to only flow in one direction. I suspect a bad reed valve - either broken (unlikely) or bent from age just enough to prevent it from sealing against the air pressure in the crank case.
 
Also questioning the statement you were "due for carbs". I don't hear this unless it has sat for long periods of time with old fuel. I would have tested fuel pump before dropping $600 plus. There could be two issues but need to eliminate easy ones.

Sent from my SM-G973U using Tapatalk

 
If a mechanic tell me its the carbs and I drop 670 on it, if its not the carbs-- he is going to need a cop and doctor and lawyer in that order.
 

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