1978 Evinrude 150

[etd66ss]

I bought a non-running Evinrude 150 last week, and I'm just starting to get into it.

First problem I dealt with yesterday was the reason the previous owner got rid of it, no spark.

I built a stand for the motor, and got it set up. I read on these forums, that the ignition switch shorting out could cause the no spark condition. Sure enough, I get great spark at each cyl. with the red plug removed, and cranking by jumping the starter directly from battery.

Next, I wanted to take a look at the compression. I got 80 psi for every cylinder. The previous owner said the engine lacked power, took forever for his boat to plane. I have not looked at the pitch of the prop yet, but 80 psi does seem about 10-15 psi too low to me, even for an old motor.

I see that this powerhead was rebuilt at some point, as I see permatex sealer all over the place, looks like whoever had it rebuilt did not want to spend money on a gasket kit. The freezeplug also does not have the model number & serial number, any way I can tell if this is a reman powerhead?

I'd like to get it running before I tear into the powerhead.

For anyone here experienced with powerheads, does 80 psi on all cylinders indicate that maybe I can get away with just honing & re-ringing? I'm concerned that this thing was already rebuilt, and bored over as far as it can go.

Another problem I'm having is the shifter is locked up. I pulled the lower unit last night, and there is no excessive corrosion, but the shifter rod does not move. What's the normal cause of this?

 

[etd66ss]

Re: 1978 Evinrude 150

I got the motor running tonight. The lower unit was off, but I attched a garden hose to the water pump tube. The port side head was hot, while the starboard head was cooled, I guess the thermostat on the left side was not opening, the plastic part of the relief valve was melted on that side, seems the previous owner ran it with a bad thermostat.

It did not run very well at all, not sure it was firing on all cylinders. I get spark on each cylinder 7/16 away though... It seemed to be popping a lot. I'm assuming the timing is way out of whack, but won't know until I check it.

I'd like to get the lower unit shift linkage free'd up, get this on a boat, and try it out before I tear it down for rebuild.

I discovered that my shifter is hydraulic, and the lower unit had milkshake gear oil in it. I'm wondering if the water in the oil rusted the hydraulic valve together?

I should be able to shift the motor in gear by hand without the engine running and driving the HYD pump, correct? I can't imagine the HYD shift can only be actuated when the motor is running, but I don't know. I'm sure someone here can tell me

Oh, one thing I noticed is the top carb does not have a choke plate? There are no holes to even mount one... Is this correct?

 

[emdsapmgr]

Re: 1978 Evinrude 150

If that engine has the original heads, the compession on that 78 150 should be in the 110 range. That's normal for a factory engine. Check the head part numbers: they should be 323456/457. If they were ever changed, that could explain the low compression. You may have to pull the lower off to determine why the shift linkage won't move. You disconnect the lower unit shift rod under the bottom carb. It has the older style belcrank system. If your lower unit oil is milky, you have water intrusion in the gearcase. Probably time for a complete reseal of the gearcase. Propshaft, carrier, drive shaft seal and shift rod seal. None of the 78 or 78 engines had a choke plate on the top carb. My 79 200 was not a good starter the whole time I owned it. An inductive timing light will tell you a lot about the quality of spark on each plugwire when you run the engine. Depending on the taper/wear on the cyl walls, you may be able to hone/re-ring the pistons. If you are going to work on this engine, a factory service manual from Ken Cook Co, in Milwaukee (outboardbooks.com) is really helpful.

 

[etd66ss]

Re: 1978 Evinrude 150

I got my service manual in the mail yesterday.

Hmm, just bought a starboard 0325557 head off eBay to replace mine, as the lower spark plug hole was messed up, then subsequently "fixed". It was cheaper to buy a used head than a timsert kit & insert. I hope I don't end up with one high comp head, and one low comp head. Though, I thought it was just different gaskets to lower the comp.

The lower unit is off, and I hope the shifter problem becomes obvious when I tear it apart.

I'm going into this rebuild expecting to bore the block, new pistons, and probably many new ignition parts, we'll see how it goes...

As far as the inductive timing light, I have one. How will that indicate quality of spark? Light intensity? I'm wondering how I will know what "good" is.

 

[emdsapmgr]

Re: 1978 Evinrude 150

I believe a 557 head is a low compression bathtub head. Not the same configuration as the higher compression heads which came on the engine from the factory. The flashes in the timing light will show intermittent spark, no spark, or weak spark, when compared to the other plug wires.

 

[etd66ss]

Re: 1978 Evinrude 150

Hmm, I'll have to check my part numbers. The 557 head in the part number book says it's a replacement for 457. But I see no replacement for the 456. So confused.

Anyone know the actual physical differences in the low/high comp head?

I did find this: http://www.crowleymarine.com/johnson-evinrude/parts/36451.cfm

 

[etd66ss]

Re: 1978 Evinrude 150

I just got home and checked the heads, they are:

Port: 328324
Star: 328325

Are these high comp or low comp?

Can I replace the starboard one with the 557 I bought on eBay?

It seems my current heads heads are from a 1983 motor, not a 1978...

Did OMC put the low compression heads on at the factory?

 

[emdsapmgr]

Re: 1978 Evinrude 150

Someone has changed your original heads-perhaps they were damaged and replaced at one point during a powerhead overhaul. The original factory high compression heads 456/457 are probably no longer available, so someone put the 324/325 heads on the powerhead. Likely these are the ones that the factory says supercede the older heads. These heads are the low compression bathtub heads and is likely much of the reason you have the compression readings that you indicate. The problem with using these older heads is that your carbs are jetted to flow slightly more fuel to keep the older high compression heads cool. Your current jetting may be off slightly, causing some overfueling at higher rpm's. You will see degraded performance with these heads.

 

[etd66ss]

Re: 1978 Evinrude 150

Likely these are the ones that the factory says supercede the older heads.

The 324/325 heads do not show up in the 1978 on-line parts manual as supercedes, only the 557 shows up as a supercede for the 457, the 456 has no supercede in the 1978 parts manual. As seen here: http://www.marineengine.com/parts/johnson-evinrude-parts.php?year=1978&hp=150&model=150849S&manufacturer=Evinrude&section=Cylinder+%26amp%3B+Crankcase

The 556 does not show up as an OEM head until 1980: http://www.marineengine.com/parts/johnson-evinrude-parts.php?year=1980&hp=150&model=E150TRLCSF&manufacturer=Evinrude&section=Cylinder+%26amp%3B+Crankcase

The 324/325 first show up in the 1983 parts manual as factory original heads (but only on some models). As seen here: http://www.marineengine.com/parts/johnson-evinrude-parts.php?year=1983&hp=150&model=E150TRLCTB&manufacturer=Evinrude&section=Cylinder+%26amp%3B+Crankcase

It seems like 1983 is the year the 324/325 heads were introduced on certain models, while the 556/557 were on some other models.

So there is some type of difference between the 556/557 & 324/325 heads, but I need confirmation that it is the compression, and not some other difference.

I have to do more checking of part numbers, but it may be that the powerhead on my outboard is from a 1983, block, heads, etc.

My theory is that the low compression heads started to show up on models in 1983, and all previous heads are high compression, less the ones from the special low compression kits. As seen here: http://www.crowleymarine.com/johnson-evinrude/parts/36451.cfm

I'm thinking if I grab a 556 for the port side, I'll have a set of high compression heads. But I'm just guessing, looking for an expert to prove/disprove my theory.

 

[emdsapmgr]

Re: 1978 Evinrude 150

The attached picture is not of a 79 head, but the pictured configuration is more like the original heads that the factory put on a 1978/79 V6. These are a higher compression head than a later bathtub head and will tend to match up better with original 1979 carbs and jetting. If your powerhead is a later (replacement powerhead) version than you think, like an 83 or 84, it will likely have the correct carbs/jetting for the 1983/84 heads. If it is the later powerhead, then your compression readings are closer to what it should be from the factory.

 

[etd66ss]

Re: 1978 Evinrude 150

Alright, guess I wasted my money on the 557 head.

Your picture finally gives me the info I need, thanks.

I did not understand what the hell you meant by "bathtub" but now I do.

So, if I locate a set of high compression heads, I can install them and simply ensure I jet the carbs via the old 78/79 specifications? No other changes besides 93 octane and correct oil? Any lead additives required in the fuel?

 

[emdsapmgr]

Re: 1978 Evinrude 150

Yes on the jetting and on using high octane fuel.

 

[etd66ss]

Re: 1978 Evinrude 150

I'm debating on whether or not to search for high comp heads.

What will I gain if I were to do so? More HP? Any other benefits?

This motor will be going on a 1972 StarCraft 18' Deep-V alum fishing boat. Not a ski/pleasure boat, etc.

 

[emdsapmgr]

Re: 1978 Evinrude 150

You probably don't need the high compression heads for your applicaion. The engine may run fine. Keep in mind-that if you are running stock factory carbs-they are jetted to dump extra fuel into the engine to keep those pistons cool (with the original heads.) Without the factory high compression heads, you are overfueling slightly. That can affect overall performance-hole shot as well as top end and overall fuel economy. I'm not making any recommendation either way, just letting you know what some of the issues are.

 

[etd66ss]

Re: 1978 Evinrude 150

Yeah, I understand the carb jet issue, and will look into that when I rebuild the carbs. I'm just trying to get a handle on the difference between the two setups. It appears in the MID 1980's you could buy a model with the low comp heads for use with 87 octane and smaller jets, or a model with high comp heads, larger jets requiring 93 octane. There must have been advantages/disadvantages to these setups with an accompanying sales pitch by dealers. Just want all the info I can get before I decide which setup to build.

 

[etd66ss]

Re: 1978 Evinrude 150

I removed the heads, electrical, carbs, etc from the powerhead and pulled it off the exhaust housing last night.

It looks to me like the previous rebuild was a hone job and new rings. Unfortunately, the mechanic may not have set the ring gap. 2 of the 6 cylinders have a gouge in the cyl wall, that to me, looks like from the end of a ring. The gouges are maybe .040" wide by about .0005"-.0010" deep. Some of the pistons have a bit of slop from side to side in the bore, maybe .030" total slop.

Good thing is, they are STD pistons, so I have room to bore if I need to.

I'm wondering, if a single .001" deep scratch warrants boring? I will dissemble further and use a bore gauge on the cylinders to see if they are within spec. If they are, I'm wondering what to do about these scores.