Newbie needs guidance

[terry 5.2m]

Hello all,

New to the forum and I have been trying to search and educate myself as much as possible before posting thie, however, it is becoming a little overwhelming.

I have a 1978 Terry 5.2M with a 1977 Johnson 115ETL77S.

The boat is in what I feel to be good condition but the motor needs some TLC.

I just purchased the boat last Sunday. While on the test drive I noticed the idle was rough but at WOT it hummed around pretty good and I didnt notice any missing, hesitation etc. granted I am by no means an OB expert.

At idle however, it is a different story. The high speed idle needs to be engaged for it to stay idling.

I purchased the boat based on faith that it just needed some TLC. The person I bought the boat from said he couldn't remember when he had it out last but has it running on muffs July 4th weekend.

So last night I bought a transfer pump and removed all the gas from the tank. I also disconnected the fuel line to the motor, removed the connection and used the prime bulb to make sure I had all the gas out of the tank. The first gal I put into a milk jug and after letting it settle there was indeed water in the gas or it had seperated....maybe 8oz worth. I continued to pump the gas out and towards the end I put some more gas in a different milk jug to see if there was more water. At this point the gas was form what I could tell clean. This makes sense as water is heavier than oil/gas and the boat is on the jack wheel jacked as high as it could go so the gas would fall toward the primer tube as it neared the end.

This bring me to my "what I wanna hear" question.

1. Do I need to rebuild the carbs? Or can I refill with fresh 50:1 mixture, hook up to muffs and see what I got. The plugs are pretty black so I was going to clean them first and double check the gap to be 0.03. I also have carb cleaner I was going to spray into the carbs while the engine was running. I also have a can of "Tuner" Carbon cleaner.

2. I want to check the water flow for the pump/impeller. The guy I bought it from said he replaced the impeller and fluid this season but I still wish to verify. On this older model from what I have read the water comes out of the exhaust ports and/or the prop area (telltale?). This is where I am fuzzy. I bought a Solec (I know the O&M is the best way to go) and it mentions to be carful not to have >45psi on the muffs. I am going to use a std home, city water supplied, garden hose. To my knowledge I do not have a pressure gauge but I will double check.
a. Is this a true concern? I had though about buying a water trough from TSC to submerse the motor as I think that would exhibit a more accurate load.
b. Where should I see water exiting and how strong of a stream should I have? I do not have a temp gun to monitor the head temp.

If it ran good at WOT do I need to be concerned with compression check?

thanks in advance and I apologize for the long post.

PS see attached pics of boa...hardly anyone including myself has ever heard of a Terry.

Scott

 

[Joe Reeves]

Re: Newbie needs guidance

Scott... To obtain a good idle, the major qualities that a engine must have are proper compression, proper spark, and internally clean carburetors. Various other qualities exist of course but these are the trouble shooting points regardless of whatever problem exists. Soooooooo.............

With all of the spark plugs removed, check the compression which should be approximately 100+ psi and even on all cylinders. What readings do you get?

With the spark plugs still removed, check the spark which should jump a 7/16" gap with a strong blue lightning like flame... a real SNAP! Does it?

BTW, spark plugs should be Champion QL77JC4 plugs gapped at either .040 or .030 (which ever gap works best for you).

If the two areas above are as they should be, then the cause of a poor idle is usually contributed to fouled carburetors. In which case, remove, clean, and rebuild them as needed.

NOTE: Spraying carburetor cleaner into a carburetor throat is bypassing all functions of a carburetor. The mixture you're spraying is simply being fed directly into the crankcase.

That engine does not have a water telltale outlet, and the majority of the water flows out thru the propeller. Water may also exit the exhaust relief holes (explained below). When running a high horsepower engine (yours) on a flushette, have the water pressure turned on full force.

(Exhaust Relief Ports - Exhaust Housing (Inner/Outer)
(J Reeves)

The long housing between the powerhead and the lower unit is called the exhaust housing. There is a inner housing within it that has a heavy duty seal around the bottom of it, or heavy duty seals around a inner extension between the housing and the lower unit.

The red hot exhaust travels down thru that inner tube and out the propeller with a somewhat supply of water to cool the propeller hub. A good amount of water surrounds and fills the space between the outer and inner tube, otherwise the outer housing would get so hot that the paint would burn off.

Some water pumps, for some reason (differing even when new) exert a great amount of water pressure, and if the exhaust housing seals are in perfect condition, the water fills the tube to a point of overflowing.

This brings into play those two holes or slots, whichever the engine might have, at the top rear portion of the exhaust housing just below the powerhead.

Now, if those two holes/slots weren't there, water would continue to flow up into the cylinders. Water not flowing out of those holes is no concern for alarm UNLESS that outer housing suddenly becomes extremely hot..... the warning horn should sound long before that happens.

The main reason for those holes being there (exhaust relief holes) is that when at an idle, there is an extreme amount of resistance encountered by the exhaust trying to escape due the fact that the outlet via the propeller is now blocked by a wall of water. The escape route in this case is for the exhaust to escape out those two holes, otherwise the engine would slow down quite quickly and die. If exhaust cannot escape, air/fuel cannot gain entrance to the engine.

Warning Horn Test: Engine NOT RUNNING, key in ON position, ground out one of the TAN wires you'll see protruding from the cylinder heads. The horn should sound steadily and constantly when either of those two wires are gounded. If the horn does not sound, find out why as that's the only warning you'll receive should the engine overheat.

(Spark Tester - Home Made)
(J. Reeves)

You can use a medium size philips screwdriver inserted into the spark plug boot spring connector, then hold the screwdriver shank approximately 7/16" away from the block to check the spark or build the following:

A spark tester can be made with a piece of 1x4 or 1x6, drive a few finishing nails through it, then bend the pointed ends at a right angle. You can then adjust the gap by simply twisting the nail(s). Solder a spark plug wire to one which you can connect to the spark plug boots, and a ground wire of some kind to the other to connect to the powerhead somewhere. Use small alligator clips on the other end of the wires to connect to ground and to the spark plug connector that exists inside of the rubber plug boot.

Using the above, one could easily build a spark tester whereas they could connect 2, 4, 6, or 8 cylinders all at one time. The ground nail being straight up, the others being bent, aimed at the ground nail. A typical 4 cylinder tester follows:


..........X1..........X2

.................X..(grd)

..........X3..........X4

Compression gauges are cheap.... Wal*Mart, K-Mart, just about everywhere.

Let us know what you find.

 

[terry 5.2m]

Re: Newbie needs guidance

Thank you sir.

I plan on buying a compression checker and spark tester on the way home, however, I am still unclear regarding how much flow I should see from the impeller.

I really do not want to drop the lower unit to check the impeller as it seems pretty extensive.

I tried looking for a horn on my control lever but I did nto see one. I will check for the tan wires for the over temp but is it possible this year of motor did not have one.

I have not cleaned the fuel filter ye but plan on doing so. It is my undertanding this motor has a cleanable screen inside the fuel pump. I do not see a resevoir in the boat hull for a VRO(?) oil injection system.

Shoudl I remove the gas tank or do you feel I have doen all I can do by pumping out all the old gas?

thanks

Scott

 

[Joe Reeves]

Re: Newbie needs guidance

The 1977 115hp Evinrude/Johnson does not have a VRO. The VRO was not used until 1984.

You can not see the water flow from the impeller. The holes that you see at the rear of the lower unit just above the cavitation plate are the thermostat water relief outlet holes. Water flows out those holes only when the thermostat opens.... the rest of the water is being flushed out thru the propeller (unless some is flowing out the exhaust relief holes mentioned earlier).

If you have the standard white OMC control box, the warning horn would be inside it. The engine absolutely has one! Do the test I mentioned (repeated here) to locate the horn if it is operating properly. If the test shows that the horn sounds, then if the engine starts to get to a point whereas the engine will overheat, the warning horn will sound and notify you. The horn sounds off before the engine gets hot enough to do any damage.

Warning Horn Test: Engine NOT RUNNING, key in ON position, ground out one of the TAN wires you'll see protruding from the cylinder heads. The horn should sound steadily and constantly when either of those two wires are gounded. If the horn does not sound, find out why as that's the only warning you'll receive should the engine overheat.

If the gas smells like gas and you see no water, use it. Stale bad gas has a smell that would send a drunken skunk heading for the hills. No one can mistake that stale smell.

 

[terry 5.2m]

Re: Newbie needs guidance

Well I spent several hours friday working on my motor.

I bout a water trough for TSC to better simulate the under load conditions and it worked great. I made sure I kept the tank completely full which had the water above the pump.

First I fired it up as is so my buddy and I could better look at it and hear it. It had a stumble on idle just as before with the idle around 600rpm and dying if the high speed idle was not adjusted. I beleive it should be 650-700rpm.

I bought a spark gap checker and compression checker. After reading the Solec manual on checking the spark realizing I had to somehow ground the plug wires I opted out of the spark checker. How do you do this?

After taking the exisitng plugs out an analyzing them...after reading and debating I simply came to the conclusion that I was going to spray carb cleaner in it. The plugs were simply sooty and I had already drained all the bad gas out, my sniffer isnt so good, but there was a clear indication of water in the gas.

Put new gas, 89 octane, and synthetic mix. Sprayed carb cleaner, 1/4 can while running not allowing it to die. gapped and changed the plugs to the listed Champions. Fired the engine up and immediate improvement...not perfect but improvement over the before fresh gas, carb cleaner and plugs. After letting it warm up at 1200-1500rpm I sprayed some Johnson/OMC engine tune up per the bottles instructions. Let it soak for 16hours.

The next morning when I went out to take another look I saw black gunk around my propeller front and rear with some dripping down the area below the propeller(Not sure what that area is called). Instantly paniced thinking I blew the seal. At this point I thought I would check the lowert unit oil level as I thought this was what I was seeing.

Opened the top vent. When I opened the top plug I was expecting soem oil to just come over the edge indicating it was properly filled. No lube came out so I started fearing the worse. I opened the drain plug and let the lube drain out. I was lookind for the lube to be milky as the Solec described. (I assume this means milky white in color????). At first there was just a squirt of milky color but I also read this could be from the level too low. After all the oil drained out it had a clean texture (no grit) and saw no mily white color to it at all. It did appear used/dirty. Still afraid that it had blown the seal I removed the prop and thrust bearing etc but saw no leakage from the prop seal...only grease. Just by chance while I was working on the prop I took a deep breath and smelled a chemical aroma....remember the black liquid? I took a good whiff of the black stuff and compared the smell to the lower unit lube and determined the black stuff was indeed from carbon being blown out from the engine tuner gunk.

"convinced" I was ok I refilled the lower unit...buttoned her up and headed out for a maiden voyage, with a friend of course.

Idle was still not perfect but my goodness it was so much better. She didnt die on me and at WOT she ran like a top. I still think the carbs could use a rebuild, low speed side. That with a timing check and idle speed check this baby will be perfect!

I bought a temp gun to check the head temps while on the lake. While I didnt check it immediately after getting up to temp when I shut her off, was distracted by a phone call so it sat for 5-10 minutes before checking, the temps of all four were 119ish. Started back up and ran for 5 or so minutes. Shut back down and the temps were all around 123F. So while the t-stat may have not had a chance to open it must be getting good cooling. If the Tsat was stuck open it would cause a poor idle condition or poor fuel econ?

When I got home I visually checked my lower unit for leakage and nothing. I plan on actually checking the level by removing the upper plug. I filled it until lube just started coming out of the vent plug so it should still be at that level if no leaks.

Thanks for all the help.

 

[Joe Reeves]

Re: Newbie needs guidance

Sounds like you've got it pretty well cured. The idle thing, if it sounds like a mild backfire at the carburetor area, that normally indicates that a idle jet is slightly too small or possible gummed somewhat (2 to a carb). You can determine which carburetor and which throat is the problem simply by having the engine running, the carburetor face plate remove, then stick two fingers into the carburetor throat acting as a manual choke. When the engine smooths out, you've found the offending jet.

I'm not absolutely sure when those thermostats open but I believe it's around 143 degrees so the engine will normally run slightly hotter than that. Another member might jump in here with the exact thermo opening degree mark.

(Thermostat Purpose)
(J. Reeves)

Many engines are considered high performance engines and demand a thermostat(s), and many smaller hp engines also require a thermostat for the following reason. The pistons actually distort/twist off round when running. The thermostat is required to keep the outer wall surrounding the steel cylinder, and the cylinder wall itself at a temperture to compensate for the distortion.

With the thermostat removed, the difference in temperture between the inside the cylinder and the water jacket quickly reaches a point whereas (in effect) you have a oblong piston running up and down a round cylinder, or vice versa. Bottom line is without the thermostat, the piston and cylinder wall could be damaged in a short period of time.

The thermostat in your car isn't there simply to have the heater function properly..... think about it.