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nickcan

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"So, would you guys rather fig

"So, would you guys rather fight an exhaust issue (water in the cowling) on a mid 80's model 40hp Merc, or try to replace all the electrical on a similar year model 90hp?

I've just finished restoring an 18' wood boat and those are my options.



I've have the 40 on the boat and it'll plane out but the motor chokes out as water accumulates under the cowling. The 90 is in a friend's garage and I'm told it needs a stater and reg/rect... ???"
 
"The water in the cowling can

"The water in the cowling can likely be traced to a bad powerhead base gasket.

And, since it's just a 40 horse you can remove the powerhead fairly easily by yourself without the need of a winch etc.

Might be a fairly simple 15 or 20 dollar fix, plus an hour or two of labour on your part...

A starter and regulator for a 90 horse wouldn't be that bad either - OEM would run maybe 300 bucks, but an Arco starter and regulator from CDI could have you running for about 200 bucks..."
 
"The 40hp sat up for about 5 y

"The 40hp sat up for about 5 years and was given to me at no cost. I took it to a local mechanic who went over it for me. I spent $600 with this guy and now I still have issues...

I get exhaust puffing out from the cowling. Water is coming from underneath while the motor is running. It'll idle all day on the muffs, but when out on the water, it chokes out over 50% throttle. (helps if I keep it tilted down)

Thanks for your input."
 
A good start would be to get y

A good start would be to get your money back from that clown of a mechanic! That's an easy fix.

Jeff
 
I'll be talking with him a

I'll be talking with him again real soon. It'll be much better if I have a good idea of what's going on with it.
 
"To clarify: the only way wate

"To clarify: the only way water can leak from there is that the old gaskets were not cleaned away properly (shame on him!), a new gasket was not fitted (shame on him!), silicone was used instead of a gasket (shame on him!), or the nuts (on the motor, not him) were not tightened properly (shame on him!)

Go get 'em!

Jeff"
 
"I've been hypothesizing t

"I've been hypothesizing that there was a crack in the exhaust manifold or something else of a more serious nature. I'll be happy to find that I didn't flush $600 on a lost cause!

Thanks again guys! Regardless of the outcome, I'm glad to have found such a good resource. I look forward to being able to contribute something in the future."
 
"Muffs have less backpressure

"Muffs have less backpressure than being in the water. Hence, in the water the exhaust gas is finding the easiest route out. As water is with the gas discharge, it may be leaking through through the base of the powerhead to leg contact point.


BTW, find a new tecchie...



O ja, you're welcome! We help where we can!"
 
"Serial #: 8070826 (I thin

"Serial #: 8070826 (I think it's a 1983 - what's the book say?)

By the way, I found the receipt from the guy who worked on it for me:

He Replaced the water pump, starter brushes and bendix; he also cleaned the carb. Parts included Starter drive assembly, brush set, spring set, water pump kit with seal and lower housing, as well as some miscelaneous screws, etc... (parts total: $177) The labor was over $400 for a total bill of $621.53

In my ignorance, I was under the impression that I'd be able to take to the water after that.

I suppose the gasket was not a concern for him or he assumed it was in tact.

However, I have fuel dripping from the carb when I get her running (I don't beleive that should be the case if it was serviced?)"
 
"Well, today I pulled the powe

"Well, today I pulled the powerhead. I was surprised when none of the nuts seemed really tight. It was obvious where the gasket was blown out. I got most of it off in one peice with a razor blade and scrubbed it the rest of the way with steel wool. Any tips for a novice on surface prep, or whether to use any type of sealant, how hard to torque the nuts, etc... ???

Hope have the part tomorrow.
376328.jpg
Before"">
376329.jpg
after"">
376330.jpg
head before"">
376331.jpg
head after
 
"Hate to say it, but there&#39

"Hate to say it, but there's another gasket below the cowling that needs to be changed as well or....

I use grease on one side of te gasket and nothing on the other side (so it can be removed without ripping--I'm a cheapskate).

Jeff"
 
"what Jeff said, also remove t

"what Jeff said, also remove the lower unit for re-assembly. One more thing, when you get the bottom base up there will be a plastic piece with a rubber grommet bolted to the plate where the water tube slides in, replace it. Its the first thing the exhaust melts when the engine is overheated, causing a waterpump pressure problem. If you don't change it at least look at it. Keep those drive shaft splines greased."
 
"No sealant - put the gaskets

"No sealant - put the gaskets on clean/dry - just get all the old gasket off with a scraper.

You don't have to worry about a perfectly flat surface (like you would for a head gasket), just nice and clean.

Torque the powerhead down to 10 ft pounds (or just tight, then 1/4 turn with a regular wrench) - it doesn't sound like much but you really only have to keep it tight to the leg for everything to work properly...."
 
"Looks like the leg had cracke

"Looks like the leg had cracked at some point and has been welded, perhaps? Is this a common issue?


It's a nice flat surface and I'm going to try a new gasket, if it ever arrives. I expect it will heat up and blow also. The question is, how long before that happens? I hope to get thru the summer. I don't care if I have to change gaskets every few weeks - reminds me of my ever-blowing header gaskets on my first car (1968 Camaro)

anyone want to sell me an old Merc for parts?

The sketch shows where it appears to have been cracked...
376908.jpg
leg cracks
 
"Not common to see cracks - co

"Not common to see cracks - could have been dropped, hit something etc.

However, in those locations they should not have any adverse effect on the operation of the motor..."
 
Thanks Graham.

learning as

Thanks Graham.

learning as I go!
Finding a parts motor seems like finding a needle in a haystack.
 
"It lived in Asheville NC befo

"It lived in Asheville NC before I got it. So, it's a definite possibility, but that type of damage is usually in the foot, right?

I thought it may've been extreme overheating?

I'm on the Alabama Gulf Coast where we don't worry about such things..."
 
"So Graham, the welding would&

"So Graham, the welding would've been mainly to create a uniform mating surface for the powerhead gasket?"
 
"I'm confused--it happens

"I'm confused--it happens all the time now!

Is the metal cracked? If so, you'll need new or used) parts. If not, just gasket and silicone the hell out of it and put it back together. Snug the nuts up--do NOT tighten them--and let it sit overnight. The next day tighten the nuts up good, run it 'til it's hot, then re tighten.

Jeff"
 
"I would suspect it was welded

"I would suspect it was welded (or cold welded) simply to level it up.

In that area there really is no great pressure or anything like that.

The base gasket and the channels just keep the water going where it needs to for cooling and the exhaust and water directed down the leg.

The cracks could have been caused by someone really torquing down the power head or if it was dropped with the powerhead impacting the ground first or even could just be metal fatigue (but I personally don't think that's it, just never seen it at those locations).

In any event, I would do things exactly as Jeff suggests. You only need to "just" obtain a seal at those mating points.

The powerhead should never be torqued down beyond 10 foot pounds (120 inch pounds) which is barely past the "snug" point..."
 
"I ordered the gasket and got

"I ordered the gasket and got it in two days!!! My local shop still hasn't gotten the one they ordered...

I installed it and the motor's running great on the muffs (no obvious leak between the powerhead and leg). I am splashing her for sea trials today. We have sunshine, 67 degrees, and calm water. I'll let you know how it goes!"
 
I'm sure those of you with

I'm sure those of you with experience will get a chuckle out of this....

Motor's running great but I can't get it to go in gear. What do I have to do to get the shifting shaft that drops to the foot to engage?
It moves easily back and forth. Something in the foot need to be done?
 
"The link below contains info

"The link below contains info that sorted this out for me. I restabbed the foot with both ends in neutral and everything seems to be working fine now. The upper shift shaft slips just over the splines on the lower shaft (attached to the foot) and it must've just missed when I lowered the powerhead back down.

http://forums.iboats.com/showthread.php?t=284851"
 
"Well I launched her yesterday

"Well I launched her yesterday and things went pretty well... The gasket seems to have corrected the water in the cowling issue. The motor starts easily, idles well, and doesn't miss a beat until you give it more that about 1/2 throttle. Once you give it enough to plane out it'll run well for a couple of minutes and then start loosing rpm's and die if I don't throttle back.

Am I correct in thinking this is the high-speed jet on the carb?"
 
"it is a fuel supply problem,

"it is a fuel supply problem, did you put a fresh fuel pump gasket in, is the tank vented, are there any loose lines on the fuel system sucking air? Keep the starter tight or it will break the front upper engine casting.
The high speed jet is located at the bottom of the carb behind the brass nut, 7/16 if I'm not to lubricated

PS, the reverse lock is a commen mistake along with the why don't I have reverse."
 
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