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Mariner 40B power head job, 1978 Mariner 40BE 676

Re: Mariner 40B power head job

typhoon said:
I don't think you're going overboard at all! I will run a new engine till it's warm to the touch and shut it down for a few hours, to let the gaskets and sealers extrude and set up properly.
Call it paranoia, but I never get leaks!

Regards, Andrew.
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Do you retorque it after youv'e warmed it up? Do you ever want to retorque?
Rick
 
Re: Mariner 40B power head job

Agreed, but I then add one more step: I go over and re-tighten all the bolts. You'd be surprised at how much they will tigthen after the gaskets take a set.

Jeff
 
Re: Mariner 40B power head job

fastjeff said:
Agreed, but I then add one more step: I go over and re-tighten all the bolts. You'd be surprised at how much they will tigthen after the gaskets take a set.

Jeff
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Yes, and what really suprizes me, is how easily the bolts shear off! I'd better just stay within the torque specs this time:eek:.
 
Re: Mariner 40B power head job

Yes, I have a nice little 1/4" drive torque wrench I use for those small bolts, I bought it ages ago for working on my motorcycles, got tired of stripping out case bolts.

Regards, Andrew.
 
Re: Mariner 40B power head job

Praise God!!! I ran it this morning. It started the second I turned the key! It runs very smooth. I only ran it until it warmed up and then shut it off. It took everything I had in me, but I pulled the plugs.There was no water on them.Yes!! They were a bit oily though(not black). I did put fogging oil in it; I don't know how long that takes to burn off. I also know that I going to have to readjust the carborator, because I noticed that the idle speed was high. Should I look at any thing else in that regards?
Also, I don't want to be too paranoid, but I took it up to about 1500 rpm's and I hear a low tone metallic rythem. I don't have a trained ear; maybe thats just the way it suppose to sound. I'd appreaciate any comments on that, even if I'm told to just chill-out.
Thanks, Rick:D
 
Re: Mariner 40B power head job

I took it out on the water tonight. It ran smooth; no mis-firing and very little vibration. It moved through the throttle very well too.
I do have one big concern; It is running much hotter than with the other power head. The tell-tale stream is stronger than before, but it is warm coming out. The motor is hot to the touch, but you can put your hand on it. How do I tell if it is too hot? If it is, do I need a new thermostat?
 
Re: Mariner 40B power head job

H. I. McDunnough said:
I took it out on the water tonight. It ran smooth; no mis-firing and very little vibration. It moved through the throttle very well too.
I do have one big concern; It is running much hotter than with the other power head. The tell-tale stream is stronger than before, but it is warm coming out. The motor is hot to the touch, but you can put your hand on it. How do I tell if it is too hot? If it is, do I need a new thermostat?
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If you can rest your hand on it, it's not too hot. That would indicate around 60 degrees c. Humans burn at anything over 70 degrees c.
Easiest way to tell is to borrow or buy an infrared thermometer.
However, if your telltale is strong and only warm, I think it's O.K. The telltale should be warm, it means the coolant is doing it's job.

Regards, Andrew.
 
Re: Mariner 40B power head job

Totally agree.

Most outboards operating temp is somewhere in the 130-160 degree range and many that are equipped with "overheat" sensors will not even go off until the temp is above 190 (and you wouldn't be able to touch a powerhead that hot).

So the fact you can hold your hand against it and it has a strong water flow is a positive sign.

It's possible that the thermostat was stuck open in your other one causing it to "run cold" - which is not a good thing either...
 
Re: Mariner 40B power head job

That makes sense. I think you could have put your tounge on the other power head; it ran that cool.
It's hard to believe that I owned an outboard for eight years from my limited knowledge. I just bought a new boat because I wanted to go fishing. All I ever did was turn the key and go. I wish I had paid more attention while I had a new motor. Since I took on this prodject, I now have some understanding of what I am operating.
The advice I've gotten on this forum as been invaluable. I could have never done it alone. I came to this forum from another one. It seem that they where just waiting for some idiot like me to ask something stupid, so they could show how smart they are (and cute). I didn't find that here. You guys were very helpful and I admire that.

Thanks again, Rick
 
Re: Mariner 40B power head job

If I would have to get parts for this power head, I'm going to need more info on it. I didn't get a model or a serial no. from the seller. I do know that the year is 1986. I think it was from a 6E9 twin carb oil injected motor , but even if it is, I noticed that the part nos. are different in different serial no. ranges.
Can any one help me identify it from it's markings?
On the crankcase is stamped; Y-2 67601
On the cylinder is stamped; Y-267604
Where the halves meet is etched; 835 L or V ?
On the head is stamped; 6E900
 
Re: Mariner 40B power head job

H. I. McDunnough said:
Praise God!!! I ran it this morning. It started the second I turned the key! It runs very smooth. I only ran it until it warmed up and then shut it off. It took everything I had in me, but I pulled the plugs.There was no water on them.Yes!! They were a bit oily though(not black). I did put fogging oil in it; I don't know how long that takes to burn off. I also know that I going to have to readjust the carborator, because I noticed that the idle speed was high. Should I look at any thing else in that regards?
Also, I don't want to be too paranoid, but I took it up to about 1500 rpm's and I hear a low tone metallic rythem. I don't have a trained ear; maybe thats just the way it suppose to sound. I'd appreaciate any comments on that, even if I'm told to just chill-out. Thanks, Rick:D
Click to expand...
Well, I found out yesterday what that sound was. It was the upper connecting rod banging on the cranckcase.It popped a hole right through.I tore it down today. The case had been banged on alot and the roller bearing cage was wedged in between the rod and the shaft, tying it up.In the cylinder there were lots of little peices of, I guess, melted piston.There was only one little score line.
Did I do something wrong or was this an existing problem from the powerhead I used?
 
Re: Mariner 40B power head job

That sucks. It sounds like an existing problem to me, you've barely run it. You need a lot of rpm's to melt pistons.

Regards, Andrew.
 
Re: Mariner 40B power head job

I'm going to give it one more try. I'll stick my original powerhead back on. I'm thinking that it should hold now that I have the exhaust plate properly prepared. Since the issue of the thermostat being stuck came up, I pulled it out. It didn't appear to be stuck open, but it looks like crap. I'll replace it. With it out I can see into the cylinder head cover. It looks clean; only bits of fluffy white gel. Would'nt there be slop in there if the head was leaking?
 
Re: Mariner 40B power head job

You can give the old powerhead a go, see what happens! Outboards dump their coolant overboard, so it's hard to tell anything by looking at cooling galleries, except if they're corroded or not.
Why not just buy a head gasket and have a look, clean the gasket faces and be sure it's good?

Regards, Andrew.
 
Re: Mariner 40B power head job

typhoon said:
You can give the old powerhead a go, see what happens! Outboards dump their coolant overboard, so it's hard to tell anything by looking at cooling galleries, except if they're corroded or not.
Why not just buy a head gasket and have a look, clean the gasket faces and be sure it's good? Regards, Andrew.
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Andrew, I've always followed your advise,but I had nothing to do Friday,so I put the old powerhead on as is. I took the file to it and cleaned it up real well. I tested the thermostats from both powerheads. They both open at 140, but the '78 stayed open alittle longer and it was cleaner, so I used it. The rubber grommet was in better shape on the '86, so I put it on. I had a roll of gasket mat'l(Fast sudgested buying it last time when I thought I would'nt find all my gaskets) and a half a tube of Halomar left. So, I tried my hand at cutting gaskets. He was right;EASY! I figured, I had nothing but time in it, and by now, I can tear it down and put it back together in my sleep. If it leaks, I'll just pull it off, buy a gasket kit, and do the whole thing. At least now, I'll have two more surfaces prepared, and I can be pretty certain that it's not the exhaust plate if I still get water,right?
I'll let it set this week and test it this coming week-end.
 
Re: Mariner 40B power head job

I love working on these smaller outboards, so easy to remove and replace! If you plan on keeping the motor for a while, last time the powerhead goes on, buy some new bolts that fasten it to the leg and cover them with Duralac as you assemble it.

Regards, Andrew.
 
Re: Mariner 40B power head job

Yes, the funny thing is that I'm starting to enjoy it. At first I could't because I was so nervious. I think that my failures have served to take the edge off. If I ever wrap this one up, I might welcome another prodject. From what I've read, I probably could'nt have picked a more basic motor to start on.
Thanks, I'll check out the Duralac. I've been using the OMC gasket sealer on the bolts. I've found that it protects bolts better than it seals gaskets. I've already priced the bolts before; WOW! But, if I have to tear it all down again, I'll do it right.
Rick
 
Re: Mariner 40B power head job

Started it up today.It took right off.No strange noises. Runs very quiet. Actually, It runs smoother and quieter than it ever did before! No missing at all and the tach holds steady.I warmed it up (it actually warmed up), shut it off, and retourqued. I pulled the plug and they looked perfect with no water!
 
Re: Mariner 40B power head job

I went out on the water today. It runs good;much more responsive, smooth, and quiet.
There is one thing that bothers me. At low rpms it sounds like it alternates between two"cadances". During the rougher cycle the rpms drop and sometimes stalls at idle. It smooths out after 2300rpms. I've always assumed that it was mis-firing when it did this and thought it would go away once I got the water out of the cylinders.
The other powerhead ran fine at low rpms with the same fuel system, pump, carb, intake, magneto, and coils. I don't get it. Could it be the thermostat? Can running too cold cause this?
 
Re: Mariner 40B power head job

I'd try adjusting your carb idle mixture screws a little and try to tune it out. Could be just a little lean or rich on one carb.

Regards, Andrew.
 
Re: Mariner 40B power head job

I have a single carb model. I have rebuilt the carb and replaced the jets (some one boogered them all up on a previous cleaning). It seems like I'm always turning in the idle speed screw; I wonder if it is backing out on me. Can I put Locktite on it? I've tried to adjust the mixture screw many times, but it dosen't make much differance. My manual says to turn it out from seat 2 1/8 turns, then while in gear, turn it out until it loads up, and turn it back until it picks up speed. By the time I've got it turned almost out, I still haven't heard anything. What does it mean, "to load up four cycles"?
Rick
 
Re: Mariner 40B power head job

Got out today. After I got done fishing, I messed around with that idle mixture screw. I found the sweet spot. It runs really good. I took one last run to the far end of the lake. When I back it down, It stopped running. I took the cover off and the screw was gone. I couldn't find it, so I put my finger over the hole and ran it back to the ramp. I found it in the lower cowl when I got home.
Did I have it backed-out to far? I backed it out until it began to struggle. I turned it back in until it was as smooth as it would get at idle. Then, I turned it in alittle more to improve exceleration. It seemed to be just right. The screw is from a rebuild kit. Do I need to do something to it?
 
Re: Mariner 40B power head job

To me it sounds like you need to add something (Loktite or similar) to the thread to stop it falling out, you can't go on like that. I'd make sure that whatever you use doesn't make it's way to the end of the thread and obstruct or stop the air flow all together - use just enough to do the job not enough to cover the bolt.
 
H. I. McDunnough said:
I have a 1978 Mariner 40BE 676 that I am trying to put in service. When I first bought it, I had a mechanic look it over. He said it had good compression, but that the plugs were wet. He put new head and cover gaskets on it. I later noticed that they were wet again. He replaced them again, and then, I retorqued it again at the begining of this season.I notice that now my bottom plug is wet. It has been sudgested to me that it is the exhaust cover that is leaking. This is all new to me; I've never messed with such things, but I've done so much to this motor that I'm pretty familiar with it. I'm going to replace the exhaust cover gasket. I'm also planning on replacing the exhaust plate gasket at the bottom of the power head. I noticed some water spray on the intake manifold and the exhaust plate gasket looks like a more likely suspect. I'm ready to order the gaskets. I'm just not sure if it's every thing I need, if I should use gasket sealer, ect., or if I should put never-sieze on the bolts. Well, most importantly, am I doing the right thing? Here's what I'm getting: 2 exhaust cover gaskets; 1 driveshaft housing gasket; 1 upper housing gasket; 1 exhaust tube gasket;and 1 exhaust tube seal.
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hello!....looks like I'm in for this ride now too!!....could you tell me where you got your gaskets from please?
 
Hello Steven,
SeaWay Marine was very helpful; ask for Jack. Ebay can be less expensive, if you can find your parts; you'll need the part numbers. I can give them to you, if you can't find them. Also Marine Engine, Crowley Marine, Marine Power Service,and Doug Russell.
 
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