What the crap have I bought into with this Mercruiser 170 rig ??

[tinydog]

1986 Wellcraft with Mercruiser 170, Bought it at a great price so I thought, Without doing my homework. Points were bad and it wouldnt start so I replaced points , condensor, cap and coil and she fired right up on the muffs so I let it run for a few and shut her down. I thought I checked the oil @ the correct level but the next day I went out and oil level was way high and smelled like gas so thought maybe I flooded it bad while working on it so I changed the oil and filter yesterday and ran it on the muffs for about 5 minutes at a time 3 times during the day and went back out this morning and oil level is high on the stick and smells like gas again. I pulled each plug wire one at a time while running and all had an effect on motor. Ive read enough to know about the fuel pump tube which goes to the carb if the diaphram bust on the fuel pump and its dry. Fuel pump ? Could a screwed up carb cause this and still run okay ? Or could an internal motor problem be causing this ? Any input would be greatly appreciated. Im about to abort this mission and go back to something with an outboard. This is my 1st inboard.

 

[Don S]

Re: What the crap have I bought into with this Mercruiser 170 rig ??

Replace the fuel pump. Depending on what is leaking, it will leak towards the carb or the engine. In your case it's the engine.

 

[osborne looney]

Re: What the crap have I bought into with this Mercruiser 170 rig ??

sounds like you have a pressure build up somewhere in tank ? or bad needle & seat ? try running with fuel cap loose -- check tank vent hose ? do a leak down on needle & seat which more than likely it is the culprit

 

[tinydog]

Re: What the crap have I bought into with this Mercruiser 170 rig ??

Replace the fuel pump. Depending on what is leaking, it will leak towards the carb or the engine. In your case it's the engine.

If I pull the fuel pump is there a way to verify its the pump leaking ? Just trying not to tie to much money up in this thing until Ive had it on the water and sure there is no major issues.

 

[tinydog]

Re: What the crap have I bought into with this Mercruiser 170 rig ??

sounds like you have a pressure build up somewhere in tank ? or bad needle & seat ? try running with fuel cap loose -- check tank vent hose ? do a leak down on needle & seat which more than likely it is the culprit

You lost me on leak down of needle and seat. How is this done ? Thanks.

 

[Don S]

Re: What the crap have I bought into with this Mercruiser 170 rig ??

The pump is the only place you can get that much gas while running. If it was going into the carb, the engine would flood out.

You can remove the pump, block of the carb port, hook up a fuel supply to the inlet and operate the pump manually to see the leak.

 

[tinydog]

Re: What the crap have I bought into with this Mercruiser 170 rig ??

The pump is the only place you can get that much gas while running. If it was going into the carb, the engine would flood out.

You can remove the pump, block of the carb port, hook up a fuel supply to the inlet and operate the pump manually to see the leak.

Thanks ! As soon as this fricken rain that set in for the whole weekend lets up I will go pull the pump and let you know what I found.

 

[tinydog]

Re: What the crap have I bought into with this Mercruiser 170 rig ??

Pulled the pump and block the outlet and pumped with no sign of gas coming out around the plunger while holding under pressure but it was very clean in there if that means anything. Ordered new one anyway but is it possible that the carb could be dumping enough gas while engine is sitting to show on the dip stick ? and still crank and run ok. Thanks

 

[Don S]

Re: What the crap have I bought into with this Mercruiser 170 rig ??

is it possible that the carb could be dumping enough gas while engine is sitting to show on the dip stick ?

No. it would just puddle up in the manifold and evaporate.

 

[tinydog]

Re: What the crap have I bought into with this Mercruiser 170 rig ??

Just discovered this motor has been sitting for a while and it has some serious blow by when running, To the point that I can put my finger over the breather hole leading to the flame arrestor for about 15 seconds and its like a compressor has pumped up when I let off. Could this be pushing gas into the oil and still run ok or would it all still be burned ? Starting to look like if I want this boat Im gonna have spend some money.

 

[Bondo]

Re: What the crap have I bought into with this Mercruiser 170 rig ??

Starting to look like if I want this boat Im gonna have spend some money.

Ayuh,.... Do a compression test, 'n see what ya got...

Ya might consider partin' it out, or sellin' it, 'n goin' for another boat.....

1 without a 470...

 

[tinydog]

Re: What the crap have I bought into with this Mercruiser 170 rig ??

Way to nice of a boat to scrap ! Im gonna do the fuel pump change out just in case, Change the oil and filter again, maybe go with straight 40w and put some of that ring restore crap in it and just run till it drops and in the mean time be looking for a donor or a remanufactured 170 to drop in.

 

[achris]

Re: What the crap have I bought into with this Mercruiser 170 rig ??

If you like the boat so much, consider this option.... If you have the room in the engine bay, pull the 470 and part it out. Plenty of call for parts of those engines. Buy a crap boat with a nice, relatively recent V6 in it and do the swap...

Chris..

 

[Don S]

Re: What the crap have I bought into with this Mercruiser 170 rig ??

Replace the fuel pump, change the oil and test run it. Then do a compression test.
Those engines seem to have a lot of 'Blowby" even when they are in good shape. Don't go crazy thinking you have a dead engine just because you have gas in the oil.
Just an engine refresh of new bearings and rings could make it as good as new.

 

[tinydog]

Re: What the crap have I bought into with this Mercruiser 170 rig ??

I thought I read some where maybe on hear that the 170 was a unique build and gear ratio or something and it would be a real project to put something else in. Im not crazy about owning this motor because Ive read so much about it on different post but when logic steps in this thing lived 26 years and still runs just no doubt worn. So a good rebuild taken care of should out live the boat. My only hang up is with the remanufactured price of this engine.

 

[Don S]

Re: What the crap have I bought into with this Mercruiser 170 rig ??

Looks like we were posting at the same time, read my post just above yours.

 

[tinydog]

Re: What the crap have I bought into with this Mercruiser 170 rig ??

Thanks thats what Im going to do ! Ive already ordered the new fuel pump and really hope thats all the gas problem was, and then take it for a test run. I dont know about the compression but this motor is very smooth and quite, no ticks or anything and Im sure it cant be right but the clock still works and only shows 100 hrs log time and one of those hrs is mine total running on muffs 5 and 10 minutes here and there since I bought it