BigBadStang
Master Member
Posts: 1525
Registered: 6-23-2003
Location: Fairfield Twp, OH
Member Is Offline
|
![[*]](./images/xpsilver/default_icon.gif) posted on 9-7-2009 at 09:05 AM |
|
|
Need Help...78 Model 70hp Evinrude (70873C)
I'm trying to get this 70hp Evinrude going. It starts right up, idles, revs great...in the driveway. When I put it in the lake, and put it in gear,
forward or reverse, it will idle in gear, but when you try to give it any fuel, it bogs down and dies. Compression is 118,117,120. I know this has to
be something small or goofy, because it runs great otherwise. The boat does have an aftermarket dual lever control on it with no warm up lever, but
I've let the engine run for over 5 minutes before attempting to put any load on it, wit the same result. I'm at my wits end with this thing! I have
a complete manual for the engine, but I've looked through it over and over, and nothing in the book I can find points or leads to this problem.
I'm hoping someone who knows these engines can hear of this and give me something to look for.
Thanks!
|
|
|
Trippin
Senior Member
Posts: 250
Registered: 10-16-2007
Location: Science Hill
Member Is Offline
Mood: Humbly Perspicacious
|
| posted on 9-7-2009 at 09:25 AM |
|
|
Float Level. Remove carbs and reset.
Performance & reliability through comprehensive service
|
|
|
squakmeister
|
| posted on 9-7-2009 at 09:31 AM |
|
|
I've seen this problem before.
One engine had an air leak at the fuel pump and the other engine was out of synchronization
with the linkage between the throttle and the ignition advance mechanism.
If you haven't adjusted the throttle linkage synch since the last time the engine ran O.K., I
would look for a loose or cracked hose at the fuel pump and trace the fuel line back to the fuel
tank connection.
It sounds like you may have an air leak somewhere.
|
|
|
BigBadStang
Master Member
Posts: 1525
Registered: 6-23-2003
Location: Fairfield Twp, OH
Member Is Offline
|
| posted on 9-7-2009 at 10:15 AM |
|
|
| Quote: | Originally posted by Trippin
Float Level. Remove carbs and reset. |
Would you recommend rebuilding the carbs while they were off?
|
|
|
BigBadStang
Master Member
Posts: 1525
Registered: 6-23-2003
Location: Fairfield Twp, OH
Member Is Offline
|
| posted on 9-7-2009 at 10:19 AM |
|
|
| Quote: | Originally posted by squakmeister
I've seen this problem before.
One engine had an air leak at the fuel pump and the other engine was out of synchronization
with the linkage between the throttle and the ignition advance mechanism.
If you haven't adjusted the throttle linkage synch since the last time the engine ran O.K., I
would look for a loose or cracked hose at the fuel pump and trace the fuel line back to the fuel
tank connection.
It sounds like you may have an air leak somewhere. |
It has never ran "ok" since I have had it. When I bought it I took it to Personal Performance at Bob's Marine, and Brian went through it and tuned
it up, (supposedly) checked the carbs and everything, and swapped out the lower unit for me. The fuel lines under the cowl are new and the 12 gallon
Moeller tank and feed line and bulb are also new. I suppose I could rebuild/replace the fuel pump too just to make sure.
|
|
|
squakmeister
|
| posted on 9-7-2009 at 10:26 AM |
|
|
If you are going for the float level . . . .
May I suggest you take a short piece of wood (broom stick) and a rubber mallet and rap it
gently against the bowl assembly (with the engine running). It might save you some time
by jarring loose the needle and seat and fix the problem.
|
|
|
RIVERRAT
Senior Member
Posts: 308
Registered: 12-26-2004
Location: miamisburg oh/clearwater sub
Member Is Offline
Mood: wanting to be at the lake
|
| posted on 9-7-2009 at 11:22 AM |
|
|
Might check coil , have seen a bad coil do this as well
|
|
|
Trippin
Senior Member
Posts: 250
Registered: 10-16-2007
Location: Science Hill
Member Is Offline
Mood: Humbly Perspicacious
|
| posted on 9-7-2009 at 02:47 PM |
|
|
Float level, remove and reset. Yes it would be a good idea to rebuild the carbs if it has not been done in a while and the length of time between
running well has been considerable.
Performance & reliability through comprehensive service
|
|
|
Tom
Master Member
Posts: 1934
Registered: 1-1-2003
Location: Somerset, Oak Hill/Winding Ridge area
Member Is Offline
Mood: Constantly thinking of our troops and how lucky we are to have the freedoms they protect.
|
| posted on 9-7-2009 at 10:18 PM |
|
|
I mentioned it in a prior post too...
There are tiny orifices in the top of each carb's ventury area. I've used a fine stainless wire to clean mine out and after that it ran fine. Also
being an older rude. Check the floats to make sure they are air tight. If my memory serves me correctly the floats are soldered brass type. They can
develop leaks and fill with gas. Just another thing to check while rebuilding the carbs.
One of the giveaways to my problem was if you choked it while transitioning to high speed it would go on until you stopped choking it. Then it would
die out... Again, you could start it and it would idle fine. Even rev but not put it in gear and try to plane.
Get-R-Wet
in
Pulaski County!!!
|
|
|
BigBadStang
Master Member
Posts: 1525
Registered: 6-23-2003
Location: Fairfield Twp, OH
Member Is Offline
|
| posted on 9-7-2009 at 11:41 PM |
|
|
Tom, I wish I could get it off the trailer! It dies before it will even back off the trailer. 
I will clean/rebuild the carbs and replace the floats I found kits for about $17 each with new floats...then see what happens. 
Thanks for the info Trippin!
|
|
|
Clueless
Senior Member
Posts: 136
Registered: 8-9-2005
Member Is Offline
|
| posted on 9-8-2009 at 08:12 AM |
|
|
I had similar behavior with an older Johnson. Had the carburetor rebuilt and it has become the most reliable little motor I have.
|
|
|
Lighthouser
Senior Member
Posts: 102
Registered: 2-4-2007
Location: Louisville, Ky./Jamestown Resort Marina
Member Is Offline
Mood: Wanting to catch a record fish!
|
| posted on 9-29-2009 at 08:13 PM |
|
|
I have a 1973 /65 hp. Johnson on a 16 ft. aluminum v bottom. It would not get on plane.I tried carbs,timing,gas lines,etc. Replaced power pack and
it runs great.
|
|
|
Nervous_Wreck
Master Member
Posts: 4973
Registered: 8-21-2007
Location: Enon,Oh. / Al-1
Member Is Offline
Mood: Taxed Out !!
|
| posted on 9-30-2009 at 05:57 AM |
|
|
Well howdy Stang!
This little project why you haven't been on the forum for a while?
Good luck to ya. Keep us posted.
P.S. Should be a 'Ford' huh. 
When life sneeks up on you....so does time!!
|
|
|
BigBadStang
Master Member
Posts: 1525
Registered: 6-23-2003
Location: Fairfield Twp, OH
Member Is Offline
|
| posted on 9-30-2009 at 11:52 AM |
|
|
| Quote: | Originally posted by Nervous_Wreck
Well howdy Stang!
This little project why you haven't been on the forum for a while?
Good luck to ya. Keep us posted.
P.S. Should be a 'Ford' huh. |
Lol...yeah, this 'little project' along with many more 'little projects'!
If it had a Ford small, or big block in it, I would have been skippin across the water a LONG time ago! These cursed little 2 strokes!
btw...I ran all the tests in the shop manual on the electrical parts, and everything was well within spec. Going to try to get down there this weekend
to do the carbs, and I figured I may as well rebuild the fuel pump also...everything else on the fuel system will be new or rebuilt and clean.
|
|
|
Cc350
Master Member
Posts: 619
Registered: 4-17-2006
Location: Ohio / Ky GriderHill
Member Is Offline
Mood: Water Ready
|
| posted on 9-30-2009 at 12:30 PM |
|
|
We had almost the same Outboard on a pontoon and went through the same symptoms as you, it ended up being the fuel pump.
Some people are like slinkies - not really good for anything, but they still bring a smile to your face . . . When you push them down a flight of
stairs!!!
|
|
|
BigBadStang
Master Member
Posts: 1525
Registered: 6-23-2003
Location: Fairfield Twp, OH
Member Is Offline
|
| posted on 10-12-2009 at 11:47 AM |
|
|
***UPDATE***
I took the carbs off expecting the worst...you know, gas varnish and gum and such. I started with the top one and worked my way down. To my surprise
the carbs were very clean with absolutely ZERO varnish or deposits of any kind in them! I had bought the complete kits, so I went ahead and took them
apart, used carb cleaner and blew out all the passages, and reassembled. I did take note that the float level on the top carb was WAY off...too low.
The middle carb, the float was spot on, and on the bottom carb, the float was way too low also. When I drained the bowls on the bottom and top carbs,
only about 1/2 an ounce of fuel came out of each one! I took my time when I was checking/setting the floats on reassembly to make sure they were
right.
I didn't have a chance to put the boat in the water to test it out, but it started right up and idled even better than before, and it really sounds
good and revs up strong.
Now though, I have a fuel pump issue. After doing the carbs, I rebuilt the fuel pump. I must have somehow torn, or puckered the diaphragm when I was
putting it back together, because on the backside of the fuel pump, the little pressure equalization hole has fuel that comes out of it when the
primer bulb is squeezed...dammit! I am almost ready to just buy a new pump so I don't have to screw with it anymore.
Does anyone know if I can still buy the fuel lines for this outboard? I replaced them with standard fuel line, but the angles and radii the lines have
to conform to, the look like they will kink over time. Are the OE fuel lines molded? I would like to put the fitted lines on if I can still get
them.
Thanks for all the input guys!
|
|
|
Trippin
Senior Member
Posts: 250
Registered: 10-16-2007
Location: Science Hill
Member Is Offline
Mood: Humbly Perspicacious
|
| posted on 10-12-2009 at 12:22 PM |
|
|
Appearantly only one molded hose is still available for that system, 333395 Crankcase pulser hose, about 11.00 before shipping if in fact it can be
located in a warehouse, good luck.
You're better just trying to adapt some modern fuel line.
Performance & reliability through comprehensive service
|
|
|
squakmeister
|
| posted on 10-12-2009 at 12:30 PM |
|
|
Give this hose a try.
Trident SAE J1527 (1-93) USCG & ISO 8460 Type B1 #309
See bottom of webpage:
http://www.tridentmarine.com/stage/fuel.htm
|
|
|
BigBadStang
Master Member
Posts: 1525
Registered: 6-23-2003
Location: Fairfield Twp, OH
Member Is Offline
|
| posted on 10-12-2009 at 07:56 PM |
|
|
| Quote: | Originally posted by Trippin
Appearantly only one molded hose is still available for that system, 333395 Crankcase pulser hose, about 11.00 before shipping if in fact it can be
located in a warehouse, good luck.
You're better just trying to adapt some modern fuel line. |
LOL...that's about right! The Pulser Hose is darn near straight other than where it hooks to the pump!
Trippin...do you have a hook-up for a fuel pump, or should I just buy online?
btw...thanks for taking the time to look into the hoses, I DO appreciate it. 
Squak...thanks for the link! Those hoses look like they are quality, and what I may need.
|
|
|
Trippin
Senior Member
Posts: 250
Registered: 10-16-2007
Location: Science Hill
Member Is Offline
Mood: Humbly Perspicacious
|
| posted on 10-12-2009 at 09:23 PM |
|
|
Hook up?
Performance & reliability through comprehensive service
|
|
|
BigBadStang
Master Member
Posts: 1525
Registered: 6-23-2003
Location: Fairfield Twp, OH
Member Is Offline
|
| posted on 10-13-2009 at 12:14 PM |
|
|
| Quote: | Originally posted by Trippin
Hook up? |
LOL...sorry for the jargon! 'Hook-up' = a supplier, or connection to aquire something from. Sorry for the confusion.
What I was wondering is, if you have a supplier you could get a fuel pump from, or should I just try to buy one online somewhere?
|
|
|
Trippin
Senior Member
Posts: 250
Registered: 10-16-2007
Location: Science Hill
Member Is Offline
Mood: Humbly Perspicacious
|
| posted on 10-13-2009 at 11:19 PM |
|
|
Ah...Hook up, und ya' I got it...
Fuel pump assembly - about 79.00
Fuel pump rebuild kit - about 19.00
Let me know, I'm ordering a bunch of other stuff tomarro to get it by Friday cut off is 1:00.
Performance & reliability through comprehensive service
|
|
|
