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zordak
zordak Reader
4/13/21 9:30 a.m.

Bought another boat, this time a v hull 14' with Mercury outboard. I bought it last fall and it has sat until last weekend. First I put a battery in it and checked out the electrics. Everything seems to work but I  will feel better doing a rewire job when I get time. Any way I put the muffs on it, new fuel (no alcohol) and oil and fired it up. I did not see the telltale water spitting out the back of the motor so I shut it down after a minute. I am going to pull the lower end and re-build the water pump. The book says to remove the prop before dropping the lower unit, but if I am just going to re do the pump do I really need to pull the prop? 

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) GRM+ Memberand MegaDork
4/13/21 9:55 a.m.

Before you do all that:

50/50 chance that it has a thermostat.  On Mercs, the "peeing" won't happen unless the thermostat is open.  Good chance you just didn't get it warm enough to start peeing.

Run it for a few minutes.  Check it by periodically touching the head.  The thermostat should open about the time you can't touch the head anymore without swearing.

11GTCS
11GTCS HalfDork
4/13/21 11:55 a.m.

I was all Mercurys before the current Evinrude, the tell tale is there regardless of the thermostat position.   It's just 1/4" tubing, check to be sure an insect (looking at you wasps and mud daubers) hasn't filled the hole.   Run a piece of wire in to be sure it's clear.   Just water pressure from the muffs will often cause some flow out the tell tale so it could be blocked.  Replacement of the water pump impeller is a pretty easy job on the older motors I had, the only trick was making sure the shift shaft isn't moved while you have the lower unit off from what I remember.   Also, the trim tab bolt needs to come out from the top of the leg (plugged hole at the top rear of the upper part of the cavitation plate  / directly over the trim tab) or you won't be able to separate the lower unit from the mid section of the engine.   Tilt the engine to give yourself the clearance to pull the LU, the drive shaft comes with it.

Full disclosure, above applies to the old school two strokes and the Mercruiser stern drives.  I have not had wrenches on any of the new 4 stroke outboards.

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) GRM+ Memberand MegaDork
4/13/21 2:00 p.m.
11GTCS said:

I was all Mercurys before the current Evinrude, the tell tale is there regardless of the thermostat position.   

Disagree.  My 1992 25hp has a thermostat and a nipple on the housing.  It does not pee unless the stat is open.  Same goes for my early 80s 9.8hp.  My 1988 M70 does pee constantly because the nipple is on the bottom of the head, not the stat housing.

11GTCS
11GTCS HalfDork
4/13/21 7:09 p.m.

In reply to Curtis73 (Forum Supporter) :

No worries, the newest ones I ever had we’re a 1987 115 inline 6 “tower of power” I bought new and a 1989 3 cylinder 90 (technically a Mercaha, yes they were a thing) that came with the Whaler.  Both of those peed as soon as they started.    FWIW the 90 Etec that replaced it has water flow out of the tell tale from start up as well.     The smaller Mercury engines were made in a joint venture with Tohatsu at some point so they may have had different features.  

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) GRM+ Memberand MegaDork
4/13/21 9:29 p.m.
11GTCS said:

In reply to Curtis73 (Forum Supporter) :

No worries, the newest ones I ever had we’re a 1987 115 inline 6 “tower of power” 

Good lord I love those things.  They sounded like they were ready to kill something.

11GTCS
11GTCS HalfDork
4/14/21 7:37 a.m.

In reply to Curtis73 (Forum Supporter) :

I loved the sound, no doubt one of the most iconic outboard sounds especially over 4,000 RPM.  I don't miss syncing the 3 carbs or the "psst., buddy your boat's on fire" comments on cold starts with all the oil smoke.   The direct injection Evinrude has spoiled me, the next outboard should there be one will be a 4 stroke though as Evinrude is no more.

zordak
zordak Reader
4/14/21 9:16 a.m.

Thanks, I will take another look before tearing in to it.

1SlowVW
1SlowVW HalfDork
4/14/21 10:22 a.m.
Curtis73 (Forum Supporter) said:
11GTCS said:

In reply to Curtis73 (Forum Supporter) :

No worries, the newest ones I ever had we’re a 1987 115 inline 6 “tower of power” 

Good lord I love those things.  They sounded like they were ready to kill something.

They were ready to kill the driver. 

11GTCS
11GTCS HalfDork
4/14/21 11:42 a.m.

In reply to zordak :

Post a picture if you can so we know what vintage of Mercury it is.   From Curtis' experience above it appears the answer is age and model dependent.   Still worth chasing out the telltale hole to be sure nothing has taken up residence.

11GTCS
11GTCS HalfDork
4/14/21 11:43 a.m.

In reply to 1SlowVW :

You may be right but you have to agree they're one of the best sounding 2 strokes especially WFO....   LOL.      

1SlowVW
1SlowVW HalfDork
4/14/21 1:24 p.m.

In reply to 11GTCS :

I grew up on 3 cylinder snowmobiles.

I adore a good two stroke. 

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) GRM+ Memberand MegaDork
4/14/21 2:26 p.m.

Not to derail, but nothing sounds better than the 2.5L, and continue watching to see them hit 8000 rpms and 117 mph.

https://youtu.be/F7x_e5m0R2Y?t=20

 

1SlowVW
1SlowVW HalfDork
4/14/21 5:50 p.m.

In reply to Curtis73 (Forum Supporter) :

Yeah, but those are just about unobtainium. 

zordak
zordak Reader
4/15/21 7:48 p.m.

Here are a couple of pics.

I think the tell tale ports are the square ones in the first pic.

 

11GTCS
11GTCS HalfDork
4/15/21 8:21 p.m.

Hi.  So that’s a mid 60’s in-line 4 cylinder/ 65 HP engine.   The square ports are for exhaust at idle and slow speeds, not the cooling tell tale.   Typically just exhaust smoke out of those ports.  In the water once you apply any significant amount of throttle (above 1,500 RPM or so) the exhaust diverts under water through the propeller hub.   

I can’t see it on the left hand (looking forward) side, so it may be on the control plug side and should be on the bottom edge of the part just above the square port section.    Look for a hole about a quarter inch in diameter.   It would make sense for it to be on that side of the engine as the typical boat helm is on the right hand side so you’d see the tell tale from the driver’s seat. If you’re running it on the earmuffs with good water supply you should have water coming out the tell tale at all times the engine is running with that vintage engine.  

I cut my boating teeth on the 1973 / 50 HP version of that engine.  It was in the family until the  early 2000’s.  My dad sold it to one of my nephew’s friends, it’s probably still going out there somewhere. 

zordak
zordak Reader
4/19/21 5:56 p.m.

O.K. back from camping. Looked over the motor and found the tell tale hole on the starboard side. Yes it was clogged. I found that there is a hose that connects the hole to the engine block. I connected the muffs up and fired it up. After a minute or so water started coming  out of the tell tale. It did not shoot out in a stream but just kind of poured out. The stream did gain pressure with higher RPM. I am going to finish preparing the boat and take it out to see how it runs.

11GTCS
11GTCS HalfDork
4/19/21 7:41 p.m.

In reply to zordak :

Ok, that’s great.  A poor stream is a likely indication of the impeller in the water pump being worn, they take a set with age and the vanes don’t stay in contact with the walls of the water pump housing. Probably a good idea to get the kit and change it out.  

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) GRM+ Memberand MegaDork
4/19/21 8:52 p.m.

I've had two Mercs from that era.  For the most part, they should pee a steady stream from the pee hole to the lake.  They shouldn't be wimpy enough that it separates into "drops."

That's my basic guideline for 60s/70s Mercs.  If it's a solid stream to the lake, you're good.  This isn't always 100% true, but let's call it a guide.  I had a 68 Merc 65 that no matter what I did, it wouldn't keep a steady stream, but it ran for 30 years (and might still be running today with its new owner) and never overheated.  But the other Mercs I had in that generation all kept a steady stream. 

Once you get to the late 80s Mercs in the same size (70-150 hp), the pee stream is so strong that it almost makes more noise hitting the lake than the idling of the motor.

zordak
zordak Reader
4/21/21 9:09 a.m.

After getting the lawn tractor running again(bad ground) I decided to go ahead and rebuild the water pump. I will feel better about running the boat if I know it shouldn't over heat when done. There are not any gauges other than the speedometer and that needs a new (correct me if I am wrong) pitot on the back of the boat and a new hose run forward.

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) GRM+ Memberand MegaDork
4/21/21 10:15 a.m.

Yup.  New Pitot and hose are in order, but it may not be a perfect fix if the speedo itself is damaged.

Pitot/pressure speedos are notoriously incorrect, but you can "calibrate" it with GPS and changing the angle of the pitot.... which is great until you bump the pitot putting it on a trailer or drag it on the bottom.

I gave up and used my phone GPS to show speed.  The closest I could get mine to accurate was off by about 10 mph

zordak
zordak Reader
4/25/21 3:36 p.m.

Surprisingly the screws and nuts came off and the lower end came off with out problems. After opening the water pump I found this.

So 11GTCS was right the impeller had taken a set. After reassembling the pump my first attempt to re install the lower unit with the cooling tube in the lower unit, I damaged the cooling tube. After a trip to the hardware store to get a piece of 1/2" copper tube, I cut another one to length and tried to install with the tube in the upper half first and using the guide tube in the lower unit. I got closer but not yet. After some electrical tape on the lower end of the tube to help line it up better the third time it slid in just fine. A trial run of the motor showed a nice strong stream out of the tell tale at idle and spraying out at higher RPM. The motor seemed to run a little rough so I checked for spark with a timing light. The timing light got a signal on all 4 wires so I am hoping with more fresh gas/ oil mix and getting it out and putting some load on the motor it will clear it self out. And yes I drained out all the gas that was in it from last year before starting this year so it did have fresh gas/ oil for all the testing.

zordak
zordak Reader
4/27/21 12:46 p.m.

Maiden voyage (at least for me) this morning. Engine fired up right away, will get up on plane fairly easily, actually a bit more harsh than the tri hull I had (very mild chop on the river with wind blowing up stream). A plate on the boat says 110 hp but if I put that much power on it it would just fly. I need to figure out on the hight speed run back to the dock it just quit. Re-started right away and was able to run around on reduced power for awhile after that, but I feel further investigation is in order. I am thinking fuel filter or pump.

ultraclyde
ultraclyde UltimaDork
4/27/21 1:11 p.m.

If you have the normal fuel hose with primer bulb setup it could be a suspect too. The inner lining of the hose likes to separate with age and clog or restrict the line. It often does it with no clues or warning. I actually carry a spare when I'm on the water. 

11GTCS
11GTCS HalfDork
4/27/21 2:48 p.m.
zordak said:

Maiden voyage (at least for me) this morning. Engine fired up right away, will get up on plane fairly easily, actually a bit more harsh than the tri hull I had (very mild chop on the river with wind blowing up stream). A plate on the boat says 110 hp but if I put that much power on it it would just fly. I need to figure out on the hight speed run back to the dock it just quit. Re-started right away and was able to run around on reduced power for awhile after that, but I feel further investigation is in order. I am thinking fuel filter or pump.

Mercury tanks need to have the vent open to keep prime on the pump so make sure it's at least cracked open and not plugged with crud.   The fuel pump uses crankcase pulsations and the rubber on those takes a set as well.   It's another easy rebuild kit.    The older Mercury carbs have inlet filter screens that might need a cleaning too.   I'd recommend getting one of the spin on fuel filter / separator set ups, if you partially plug up a carb and run lean it can kill a 2 stroke pretty quickly.   I've got one at Overtons similar to this one:

Moeller Universal Water Separating Fuel Filter Kit With Two Filters | Overton's (overtons.com)

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