forgot to add mix to gas and a battery question

75delmagic

Cadet
Joined
Jul 7, 2007
Messages
6
Newbie here, hello all! Ok, I tried to start my 1975 70hp Evinrude, forgot to mix in oil:eek:. It did not start, did I mess anything up that would need serious repair or did I avoid serious damage? 2nd question, how much battery do I need to start this thing, I had a 650 cold crank car battery and it barely spins the starter? I may run a tape player, no speakers yet. I have seen how fast and helpful the members on this forum, that is why I joined. I will post a link to my boat project if you want to see it.

Mike
http://community.webshots.com/user/66c20tx
 

jtexas

Fleet Admiral
Joined
Oct 13, 2003
Messages
8,646
Re: forgot to add mix to gas and a battery question

welcome to the forum! nice looking boat. might want to get that battery load tested......the manual for my '79 calls for 360 CCA battery - although I use a deepcycle with 850 CCA. also note that marine batteries are constructed with heavier plates and stronger cases to withstand getting bounced around in a boat. Clean & shine all your connections from battery to solenoid to starter and from battery to engine block ground.

If you're still using the old tank in the "before" picture, I recommend tossing it out & getting a couple of six-gallon plastic tanks. Those old metal tanks start making rust after 25 or 30 years and will clog up your carburetors (don't ask me how I know). ;)

Doubtful you did any damage barely spinning it on straight gas, but a compression test will give you a clue. In fact, I'd do a compression test now for baseline figures for future diagnostics.

How long since it was last started? Check the "Awakening a sleeping outboard" thread in the Engine FAQ forum. If its been awhile, might as well go ahead and order your carb kits now, save you a lot of trouble.

If you don't know when the water pump was last changed, best do that now.

good luck.................
 

75delmagic

Cadet
Joined
Jul 7, 2007
Messages
6
Re: forgot to add mix to gas and a battery question

Thank you for the info. It was started last August, ran well, the guy had just tuned it up and it lit right up. I did get a plastic 6 gallon, new bulb, hoses, etc...I just cleaned up the terminals, but I think I will replace them, they are still pretty rough. I ordered a new impeller but when I dropped the lower unit, the old one looked pretty good, so you think it would need a water pump? How do I know, if it does not shoot water up when running? What's is needed to do a compression test? This has been a labor of love, but the boat and trailer were free, so it's all supplies and man hours. :)
 

F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
28,226
Re: forgot to add mix to gas and a battery question

Boy, talk about dumb luck! You are very lucky it didn't start. A few minutes without oil and you might as well put it out to the street for the trash pickup. But you are OK since it didn't start. Flush out the hose and carbs with mixed gas before trying it again.
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,771
Re: forgot to add mix to gas and a battery question

You need a compression gauge to test compression. They vary in price starting at about $25.00 in the auto sectioni at discount stores. The accuracy is questionable but they will work. You could use an air compressor with appropriate fittings to test accuracy and then add or delete the error to the actual readings.
 

jtexas

Fleet Admiral
Joined
Oct 13, 2003
Messages
8,646
Re: forgot to add mix to gas and a battery question

Generally, replace the impeller every couple or three years, and the full pump kit if inside the housing is scored or scratched - its not a complicated or expensive procedure, and water pump failure can be catastrophic. You probably know this, but it only takes a few seconds of dry running to damage the impeller.

Main thing about compression is, and the difference between cylinders is more important than the actual reading - lowest should be within 5% of the highest. That, and any sudden change, give you clues to the overall health of the engine. But you can't check compression unless the starter spins the flywheel.

The flywheel has to turn at least 200 RPM in order to generate enough electrical power to fire the spark plugs. Measure the voltage at the starter cable with the cable disconnected and the key turned over to start - if you get 12V (+/- half a volt or so), and the starter won't spin, it needs rebuilding. That or else the engine's seized.

an original factory shop manual will pay for itself many times over - check kencook.com or marineengine.com
 

75delmagic

Cadet
Joined
Jul 7, 2007
Messages
6
Re: forgot to add mix to gas and a battery question

I am runnin!! Well for about a minute, then is dies/stalls. Usually right after a surge in rpm's any ideas on that? Bulb stays hard, helps if I squeeze a little, fuel always spills out when I squeeze it (at the pump I think). Time for a carb kit? or am I missing something obvious?
 

rickdb1boat

Supreme Mariner
Joined
Jan 23, 2002
Messages
11,195
Re: forgot to add mix to gas and a battery question

It's running lean in one or more cylinders. Rebuild the carbs and clean them thoroughly. No fuel through the carbs means no fuel/oil in the cylinders which = bad news.
 

offshore100

Petty Officer 3rd Class
Joined
Jun 27, 2007
Messages
91
Re: forgot to add mix to gas and a battery question

That surge in rpm's indicates a lean condition, ie. you're sucking the fuel supply dry. Clean the carbs.



you beat me to it rick!
 

75delmagic

Cadet
Joined
Jul 7, 2007
Messages
6
Re: forgot to add mix to gas and a battery question

WOW thanks for the fast replies. Do I just remove them and clean them? No need to rebuild? Still have not picked up a manual, hard to swallow the extra $ when the wife is involved in the budget build. :eek:
 

offshore100

Petty Officer 3rd Class
Joined
Jun 27, 2007
Messages
91
Re: forgot to add mix to gas and a battery question

hey delli, it's a 1975 model, it's over 30 years old, buy a carb rebuild kit; mostly new gaskets. You'll need 'em.
 

75delmagic

Cadet
Joined
Jul 7, 2007
Messages
6
Re: forgot to add mix to gas and a battery question

I took it apart, and someone had already done some work in there, looked real good, cleaned it out anyway. I think the culprit was that I forgot to put the fuel pump rubber seal back, the one with the screen. :eek:I feel like a complete moron, but now I know what the carbs looks like, I did replace some fuel hoses that were worn and cracked. Now she runs smooth. I will take it out tomorrow and see how it goes on the water.
 

75delmagic

Cadet
Joined
Jul 7, 2007
Messages
6
Re: forgot to add mix to gas and a battery question

Thanks:) Got out on the lake yesterday, ran like a top. Stayed out about 45 minutes. It had been 16 years since it was last on a lake and I went to the same lake Arlington, a little, shallow, stained lake but I thought it only fitting, plus the closer lake is closed do to the high water level. Here's the 72 pulling the 75 driven by a 74 LOL :D
 

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