Experienced Old Merc Mechanics Advice Needed

[IBrokeMyFreakinNeck]

I just talked to the one guy that had my '72 merc 1150 that said he had a<br />lot of work done to the motor.<br />Well again he told me to use it as an anchor, and that the motor is jinxed.<br />He said he bought it from a mechanic, took it to 3 more mechanics, and could<br />never get it to run right, except for one time.<br />He said he could never get the boat to plane(16' fiberglass bass boat).<br /><br />I asked him what he had done to the motor, he said they had checked<br />EVERYTHING. He said the carbs were rebuilt, even to reed valves. He said he<br />never rebuilt the water pump, and doesn't know if anyone after him has. So<br />that will be on my list for sure.<br />I told him I checked compression and it has fire, and it runs good on the<br />muffs.<br />He said IT WILL run good on the muffs BUT when you put it in the water its a<br />different story. He does keep telling me he lost his "*** " on that rig,<br />meaning he spent a lot of money and then gave it to his nephew.<br /><br />I'm just wondering what you experienced inliners think of this situation. My<br />prop is coming next week and I hope to water test it on the trailer and see<br />for myself.<br /><br />Doesn't this sound like carb problems???<br /><br />What do you all think???

 

[WillyBWright]

Re: Experienced Old Merc Mechanics Advice Needed

It needs reed blocks. That requires a complete tear-down of the powerhead. You might as well go all the way and overhaul it. The labrynth seals on the reed blocks are worn out and nothing short of replacing them is going to do you a bit of good.

 

[ZmOz]

Re: Experienced Old Merc Mechanics Advice Needed

So what does it do in the water? Just die? Last year when I bought my '74 Mercury 1500 I had a very similar problem. It would start and run GREAT on the muffs. Take it out to the water and it would die if you tried to go above about 1200 RPMs. First I rebuilt the fuel pump, although I don't think it really needed it. ($4 kit) Then I got a can of deep creep from Napa, and ran the entire can through the engine. It smoked so much I was really worried the fire department was going to come. (meaning it was burning off ALOT of carbon) Brought it back into the water...still the same thing. Very very slowly eased the throttle higher and higher, and finally it just started going! Screamed along at 6kRPMs just fine. God that was a happy day...

 

[IBrokeMyFreakinNeck]

Re: Experienced Old Merc Mechanics Advice Needed

Originally posted by ZmOz:<br />So what does it do in the water? Just die? Last year when I bought my '74 Mercury 1500 I had a very similar problem. It would start and run GREAT on the muffs. Take it out to the water and it would die if you tried to go above about 1200 RPMs. First I rebuilt the fuel pump, although I don't think it really needed it. ($4 kit) Then I got a can of deep creep from Napa, and ran the entire can through the engine. It smoked so much I was really worried the fire department was going to come. (meaning it was burning off ALOT of carbon) Brought it back into the water...still the same thing. Very very slowly eased the throttle higher and higher, and finally it just started going! Screamed along at 6kRPMs just fine. God that was a happy day...

From what the guy told me it just wouldn't get the RPM's up. He didn't say it would die on him. <br />I have to wait until next week for my prop to water test it. I did get a can of Seafoam that I will run through it this weekend. I really hope that will help.(There is a fire dept right by my house, I hope they don't see the smoke and come wailing through my subdivision!)

 

[camshaft]

Re: Experienced Old Merc Mechanics Advice Needed

I hope you have better luck than me with the SeaFoam. My '72 Merc 200 (20HP) would run great for 5-10 minutes, then it would start stalling and eventually die. I could wait 5-10 minutes and start it back up. This problem would happen sometimes and sometimes it wouldn't. Anyway, I decided to use SeaFoam. I went through the same routine: starts, runs, stalls. I haven't been able to start the engine since it died - even after 2 weeks. I used the whole can of SeFoam in a 6 gal tank as the instructions said. I've heard great things about SeaFoam, I'm so I imagine that I have a unique situation. I'm going to try fuel without SeaFoam today to see if it'll start. If anyone has any suggestions, please let me know.<br /><br />Thanks

 

[Clams Canino]

Re: Experienced Old Merc Mechanics Advice Needed

Not to dispel the gloom and doom, but it could just as easily be over-propped or like ZmOs's problem indicates, the idle needles are a set a bit too tight. If it will idle down properly on the muffs, (and also in the water) it contra-indicates reeds or even reed blocks.<br /><br />A tach is a must when setting these things up properly. Even a 19 pitch might be too steep. Most of my stuff is done with a 17 and even a 15 for multiple skiiers.<br /><br />Another trick is the "two step" hole shot, where you do one throttle movement to let it spool up on the advance to a little over 2000 and then hammer it the rest of the way to open the carbs. If practiced not even a skiier can feel any delay.<br /><br />-W<br /><br />

Originally posted by WillyBWright:<br />It needs reed blocks. That requires a complete tear-down of the powerhead. You might as well go all the way and overhaul it. The labrynth seals on the reed blocks are worn out and nothing short of replacing them is going to do you a bit of good.

 

[Clams Canino]

Re: Experienced Old Merc Mechanics Advice Needed

(accidental double post - now edited)

 

[mellowyellow]

Re: Experienced Old Merc Mechanics Advice Needed

symptoms could be partially/mostly clogged exhaust.<br />no backpressure on the muffs...if this is the case<br />seafoam may help, but not as gas additive, buy the<br />aerosol cans, 1 for each carb, follow instructions.<br />won't hurt at least...<br />good luck,<br />M.Y.

 

[NEECAPRS]

Re: Experienced Old Merc Mechanics Advice Needed

Clams and Mellow are giving good advice-and logical(sometimes in short supply!). It doesn't make sense that it would run on the muffs but not in the water. You didn't mention the results of your compression check, but, if there is any then it should make the boat plane as long as you're not way overpropped, say 23" or more.<br />If you have good compression and really good fire(across good plugs), it might just be a fuel supply/idle needle problem. Exhaust restrictions can also give problems, but, you should be up and planing before those limit you.<br />Good luck and keep us posted!

 

[IBrokeMyFreakinNeck]

Re: Experienced Old Merc Mechanics Advice Needed

Thanks for all the great advice fellas. I posted my compression results on another post, they were around 125, though #3 was 115 I think.<br /><br />I put half a can of seafoam in my tank, with about 3 or 4 gallons of gas. I warmed the engine forst, then ran the foam for 5 minutes, let it sit for 15 minutes, then ran it for about 15 minutes and never saw any of the thick smoke others have experienced. I did all this a second time and still no smoke. It ran good the whole time. <br />I guess this is a good thing?

 

[wilde1j]

Re: Experienced Old Merc Mechanics Advice Needed

'72Merc1150, way too much gas and too little SeaFoam. Put a WHOLE can in one gal of gas, let the motor idle till it's all gone and stops. Let motor sit for an hour then run for ten to 15 min.

 

[IBrokeMyFreakinNeck]

Re: Experienced Old Merc Mechanics Advice Needed

Originally posted by WildeOne:<br />'72Merc1150, way too much gas and too little SeaFoam. Put a WHOLE can in one gal of gas, let the motor idle till it's all gone and stops. Let motor sit for an hour then run for ten to 15 min.

Thats what I was kind of thinking. But I was reading the directions on the bottle and "pussed out". I guess I should probably try it again. Thanks Jim.<br /><br />William

 

[Clams Canino]

Re: Experienced Old Merc Mechanics Advice Needed

I'll just add that with a 16' boat that old (read heavy), you'd be amazed at what pitches *won't* plane it out. If the motor can break 3200 and get "up on the pipe" then it'll go, if not it might sit at around 3000 and make a bow wake forever.<br /><br />-W (been there - done that)<br /><br />

Originally posted by NEECAPRS:<br /> You didn't mention the results of your compression check, but, if there is any then it should make the boat plane as long as you're not way overpropped, say 23" or more.

 

[IBrokeMyFreakinNeck]

Re: Experienced Old Merc Mechanics Advice Needed

Yeah Clams,<br /><br />I'm hoping that is the problem. I'm trying to get in touch with the previous owner again and see what pitch prop he was using, just to satisfy my curiosity. It didn't have a prop when I bought it, thats why I'm waiting for the used 19 pitch I bought.

 

[ZmOz]

Re: Experienced Old Merc Mechanics Advice Needed

Originally posted by WildeOne:<br />'72Merc1150, way too much gas and too little SeaFoam. Put a WHOLE can in one gal of gas, let the motor idle till it's all gone and stops. Let motor sit for an hour then run for ten to 15 min.

I think that is a little excessive. I would mix double what they recommend on the can and while you are burning that off use the aerosol version in the carbs. Spraying it in the carbs will clean out areas that won't get cleaned out just putting it through the gas. If this doesn't work you might want to try and take off your carbs and go at them with some carb cleaner.

 

[booka]

Re: Experienced Old Merc Mechanics Advice Needed

Back from holidays. I have 850 inline 4 same problem. Set up the idle mixture on the muffs took the boat (17 ft Nova H/Cab Glass) and got 1500 rpm and stalled. Decided to rip the covers off and have a look. With the cheese and kisses on the helm I richened the idle mixture.Turned them best part of a turn! Motor now sits on 5500 at 38 mph running 19 inch prop