1978 evinrude 70 hp fuel issue..please help

[fishing dad 2011]

Ok update on my 1978 starcraft w/ 70 hp evinrude..

Well I got a new steering cable and tilt tube and now I have steering. yay glad that part is over.
New issue arises when trying to run the motor, She fires right up if I put starting fluid in the cylinders but then it seems to flood right out when the gas hits. So I unhooked the gas line pulled out the soaked plugs cranked it over till all gas was out of cylinders hit them with starting fluid again and she fired right up and seems to run good untill the starting fluid is gone then she dies tried hooking up gas again and then same thing runs out the starting fluid then dies due to what appears to be over fueling. The rpms increased whith the cold start lever up and decreased when I put it down before it died.
I am such a noobie at this crap that I just thought I would ask on here to see if anyone has any ideas. This motor was winterized but has not been run in several years. Like I said it does fire right up no problem with starting fluid in the cylinders but it dont wanna run good clean fuel (mixed properly). the model number is 70873c its a 3 cylider 70 hp and a very clean motor except for the fule oil mixture that is now coming down the lower unit from what I assume is over fueling.
Thanks in advance for any help,
Fishingdad

Please please please can someone help???

 

[nwcove]

Re: 1978 evinrude 70 hp fuel issue..please help

first bit of advice , do not use starting fluid !!! it has no lubrication in it.

 

[fishing dad 2011]

Re: 1978 evinrude 70 hp fuel issue..please help

also does it take a min. of running before water starts to pump out because with the little time it ran(few seconds) I didnt see any water coming out just saw it going in..

 

[fishing dad 2011]

Re: 1978 evinrude 70 hp fuel issue..please help

Ok that makes sense but do you have any Ideas about the problem???

 

[AlTn]

Re: 1978 evinrude 70 hp fuel issue..please help

determine the model # and obtain an OMC Factory Service Manual..ebay, outboardbooks.com, ken cook Co, Etc...even with a vast mechanical background it'll pay for itself

 

[nwcove]

Re: 1978 evinrude 70 hp fuel issue..please help

id start with a compression test, you can usually rent a tester for cheap at your local napa/auto parts store, or buy one for $20 bucks or so. post back with numbers. try squirting a bit of premix into the carbs without the fuel line connected, just to see if it will try to start on gas.

 

[fishing dad 2011]

Re: 1978 evinrude 70 hp fuel issue..please help

I have a factory service manual for this motor and in my question I put in the model number.. I really hope I get some actual potential answers rather than pokes and shots at me. I am a noob but I am not stupid and I am mechanically inclined. The manual says nothing about fueling issues really. I admit starting fluid wasnt the best idea but I just wanted to determine if it would fire up.

 

[nwcove]

Re: 1978 evinrude 70 hp fuel issue..please help

determine the model # and obtain an OMC Factory Service Manual..ebay, outboardbooks.com, ken cook Co, Etc...even with a vast mechanical background it'll pay for itself

ditto! if you plan on keeping your rig for awhile, and maintaining it yourself, a service manual is worth its weight in gold.

 

[nwcove]

Re: 1978 evinrude 70 hp fuel issue..please help

I have a factory service manual for this motor and in my question I put in the model number.. I really hope I get some actual potential answers rather than pokes and shots at me. I am a noob but I am not stupid and I am mechanically inclined. The manual says nothing about fueling issues really. I admit starting fluid wasnt the best idea but I just wanted to determine if it would fire up.

i dont think myself or AlTn were poking or taking shots, you just need to narrow down the issue, it could be one thing, or a combination of a few things, compression is usually the first thing to check, then move on to spark, then to fuel delivery. ( thats jmo, but the order i mentioned can save wasted $$$, ie, why replace a power pack on an engine with no compression etc etc)

 

[fishing dad 2011]

Re: 1978 evinrude 70 hp fuel issue..please help

Ok thanks and sorry... I will test compression tomorrow and post numbers. and then go from there... Thanks for the replies. And just for the record I HAVE A SERVICE MANUAL, troublshooting guide does not get too specific though.

 

[AlTn]

Re: 1978 evinrude 70 hp fuel issue..please help

sorry didn't see the model no. posted...1.compression test...2.spark test <must jump 7/16" open air gap..tester available at most auto parts joints > 3. fuel..post back with the results of the first 2 .

Another problem with using starting fluid is that it'll ignite even with a very weak spark. It's also hard to determine how many cylinders are firing.

 

[fishing dad 2011]

Re: 1978 evinrude 70 hp fuel issue..please help

ok compression numbers were 91,93,91 top to bottom.. At least with the tester I was using. these numbers are approximate I think but they all were pretty close to one another and in the 90's. Spark was bright and all 3 are firing good. when I pumped the primer bulb to get fuel into the line it came out of the bottom carb in front from what appears to be some type of overflow tube. After clearing the cylinders of fuel and cleaning off the soaked plugs It almost fires up off the first bit of fuel it draws but then immediately floods itself. Do ya suppose that the carbs just need to be rebuilt since this engine sat so long??

 

[BonairII]

Re: 1978 evinrude 70 hp fuel issue..please help

Pull the carbs and give them a good cleaning. That means clean every orifice/jet/etc. Check the condition of the fuel line the runs to each carb. Probably a good idea to replace it regardless. It's only $1.50 a foot.

Set your floats. I believe the manual calls for leaving the gaskets on and flipping the carb upside down(with bowl off, obviously). The float should be 1/16" inch from gasket surface. Check you float needle and seat for wear. Bad float level and/or worn needle or seat will cause the flooding issue.

 

[AlTn]

Re: 1978 evinrude 70 hp fuel issue..please help

compresion no.'s will work and probably increase some with use and a decarb procedure..spark sounds good to go..so, yes, onto the fuel side...just follow the procedures in the manual..do one at a time so as not to mix up any parts...marineengine.com will have diagrams of your carbs..it's not uncommon for each carb, depending on location, to have slightly different jetting, pay attention to the numbers on the jets

 

[fishing dad 2011]

Re: 1978 evinrude 70 hp fuel issue..please help

these carbs have fixed jets and it calls for a special tool to remove them..Is this tool really necessary or can I use a small screwdriver as long as I am careful not to ruin any threads inside the ports?
So should I just get carb kits and rebuild them completely or do ya think I can get away with just cleaning up the bowls and floats?
It's my understanding that anytime I remove and disassemble a carb all gaskets should be replaced.

 

[AlTn]

Re: 1978 evinrude 70 hp fuel issue..please help

the dimensions for the tip of that jet removal tool are given in a thread somewhere on iboats...you can probably sacrifice a small screwdriver and grind it to fit tightly in the jet's slot, there's no problem until you find one that's in realllllly tight and the screwdriver wants to ride up the ears and the old brass starts to crack...you may never encounter this

I'd kit it myself and soak all the carb parts, minus any rubber components , over night in carb cleaning solution. Wash the parts off with water and blow compressed air though all passages, use carb cleaner in a spray can to insure they're open, inspect, and reassemble.

 

[fishing dad 2011]

Re: 1978 evinrude 70 hp fuel issue..please help

i will give it a try and see. gotta wait till tomorrow to see if our local marine supply has my kits. If ya dont mind please watch my thread and I will reply by the weekend.. I really appreciate your insight and help..

 

[BonairII]

Re: 1978 evinrude 70 hp fuel issue..please help

You may or may not need a kit. Sometimes a thorough cleaning and float reset is all that's needed. The important thing is to check the condition of the float, float needle, and float seat. And as long as the gasket between the carb body and bowl....and the carb base gasket is good, you should be good-to-go.

If you have a bad idle then maybe the welch plugs and small O-rings would need to be removed and replaced.

Just my 2 cents...

 

[fishing dad 2011]

Re: 1978 evinrude 70 hp fuel issue..please help

Ok.. my carb kits were not available today so I will have to wait. So in the meantime I decided to just try draining the carbs and tapping on the bowls to see if maybe they were just stuck. Well she fired right up and ran well at idle and minimum throttle but as soon as the rpms start building up as I apply throttle she dies right out. Time and time again same thing it does not wanna run past like half throttle.
Fires right back up though no problem but just cant give it any gas really. So anyone know what this might be?? Prolly just need to rebuild the carbs all together dont I? any help appreciated

 

[BonairII]

Re: 1978 evinrude 70 hp fuel issue..please help

Just pull 'em off and clean them. It's not hard, just tedious. Put whole assembly on a clean surface, so you don't get dirt in anything and don't lose anything.

Do one carb at a time. NAPA carries the 3/16ths fuel line for the carbs, if you need/want to replace it while your at it. It's a good idea to change it while you have the carbs off.

I used a wire from a "twist tie" to run through the small opening and jets etc. It works well. The wire is very soft so no danger of scuffing the jet holes etc.