77' Merc 200 20hp P hole/water jacket

[websurfshop]

My motor is 1977 Mercury 200 20hp ser.no. 4581417 Model 12007<br /><br />The motor is new to me(and I'm new to outboard motors), she runs fine but I am not getting any water out the "P" hose when I run it with a flush hose hooked up. Things I've done:<br /><br />1)Changed the impeller<br />2)Ran it completely assembled with a flush hose hooked up<br />3)Took it back apart and flushed the "P"(****) hose out with water/compressed air/WD40, took the the P hose fitting off the cylinder side so I can see in the water jacket(it's fine).<br />4)There is not thermostat on this model.<br /><br />After taking the lower unit back off I can push water(with garden hose and flush attachment) down from the P hose and it comes out in a 1/4" hole next to the exahaust (up inside the lower(middle?) unit directly under where the engine is mounted). I can push water up the copper hose (which inserts into the impeller housing on the lower unit) but water won't go up on top (to where the P hose is), but comes out the same 1/4" hold next to the exhaust instead.<br /><br />Do I have to have the lower unit submerged is that why it's not squirting out the P hole? Or is a stream out the P hole not required on this old model? If that's the case then whats the use of flushing the motor from salt water if it won't push up on top and over the jacket to clean the thing out? <br /><br />Next, if I have to, I am going to try to take the motor off so I can have a better look at what's going on (kinda hard with a flash light up into the lower(middle?) housing) How do I detach the gear shifter shaft when doing this (it doesn't seem to want to pull off easy after loosing the bolts holding the motor/upper unit. I thought it would just slide off but I don't want to force it.<br /><br />Any suggestions will be greatly appreciated. <br /><br />Big Mahalo.

 

[dmessy]

Re: 77' Merc 200 20hp P hole/water jacket

You should be getting a stream of water from telltale(P hose) when the flushing ears are clamped around the water intake on the lower unit and it is running.<br /> Question; when you replaced the impleller, did it come out whole or was a peice(rubber vane) was missing? From what you say, I suspect you have a peice of it clogged up somewhere. Start from the beginning, remove the lower unit. Clamp on the ears and observe water coming out the water pump assembly hole. If not disassemble pump housing and start checking for obstructions. No water in to the pump, no water out.<br />Next,with the lower unit off, hook water up to the telltale and backflush. Should get water out the copper intake tube. If not you are obstructed ,probably where the copper pipe goes into the bottom of the motor. Remove pipe and recheck with back flush. Final option if you still cann't find it is to remove the cylinder head plate to inspect the water jacket before you pull the powerhead. <br />Good luck searching.

 

[websurfshop]

Re: 77' Merc 200 20hp P hole/water jacket

Thanks I appreciate the help.<br /><br />When I flush water up the copper tube the water flows out the outlet by the exhaust (inside the and I don't see it passing by the "tell-tale" port (which I took off to look directly into the water jacket) so I think you may be right about it being where the copper tube goes into the engine.<br /><br />Question. How do I get that off (copper tube) without having a 24" long phillips head screw driver to get the retainer off? The housing is not big enough to get my hand into to get a screwdriver on it. I started taking the motor off (upper assembly) thinking it would lift off and expose the tube base so I could remove it, but it got dark before I could figure out how to disconnect the shifting shaft (it didn't just slide off). But I would prefer to not have to take the motor off to get to the tube base to remove it.

 

[websurfshop]

Re: 77' Merc 200 20hp P hole/water jacket

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[Preston]

Re: 77' Merc 200 20hp P hole/water jacket

If I am not mistaken, with the lower unit off, the copper tube should just pull out from the bottom. I believe that there is a rubber boot or grommet that it slips into. I could be wrong but I do know on the 140hp and the 150hp this is the case. <br /><br />Preston

 

[dmessy]

Re: 77' Merc 200 20hp P hole/water jacket

I believe it just pulls out(copper tube). If there is a retainer, use a peice of pipe the fits over your screwdriver handle for an extention. You know..shadetree mechanic style...<br />Did you have a peice of the impleller missing ?

 

[websurfshop]

Re: 77' Merc 200 20hp P hole/water jacket

Thanks all, I feel much like a green first mate that got hit by the sail and knocked overboard.<br /><br />No there was no impeller rubber missing. And yes the copper tube pulls out. I made a long T-handle screw driver to get the retainer screw out, but it didn't need to be removed to pull the copper tube out. Well I didn't get your responses until this morning so yesterday I took the power head off also. Everything is fine and should be back together this morning.<br /><br />Being new to this whole thing (and being paranoid of overheating the motor after it sat for so long) led to me doing all this for nothing (other than learning how the cooling works!) My ingnorance was that I was not in gear when the flush hose was hooked up! Duh! The prop has to be turning to turn the impeller to work and to generate enough pressure for it to shoot out the tell-tale. With only water pressure from the hose (without being in gear), the water will only go over the top of the cylinder and back out the exhaust/water outlet but not push out the tell-tale.<br /><br />Please no laughing.<br /><br />Thanks again. Big Mahalo (I sure some 40 lbs. Salmon got away)

 

[G DANE]

Re: 77' Merc 200 20hp P hole/water jacket

HI websurfshop<br /><br />Being bo Mercexpert, i am sure the prop does not need to be turning, as the impeller sits at the drive shaft which turns in neutral too, mounted with splined in cranck. <br /><br />Something is still wrong. Some Merc models lets water out of pee hole when thermostat is open. What leads you to the conclusion that your motor has no thermostat - most i worked on had one.

 

[brent suzkui wyble j16]

Re: 77' Merc 200 20hp P hole/water jacket

i agree with dan, never had a outboard that had to be in gear to get the impeller to work.

 

[tmcalavy]

Re: 77' Merc 200 20hp P hole/water jacket

Your 77 20 hp Merc is probably like my 74 50 hp Merc 500...DEFINITELY NO THERMOSTAT, and won't pee until you get the revs up a little. Watch ebay for a Merc shop manual for your outboard, its worth the investment. You have a good start on a long, rewarding relationship with your Merc...you know how to field strip it when it starts to con you...and they do.

 

[websurfshop]

Re: 77' Merc 200 20hp P hole/water jacket

Yes, Yes, it doesn't have to be in gear to shoot water out the "tell-tale"(or to turn the impeller for that matter). After I got it back together it works great. But this time I took the prop off and stuck it in a 50gal. can, and it shoots fine. Previously I had only hooked up with a flush hose (right under our water tank that is gravity feed) so there wasn't enough pressure I guess.<br /><br />There is not thermostat on this 1977 20hp motor.<br /><br />Thanks again.