1978 Evinrude 70 hp stalls on boat ramp.

[BigBadStang]

I have a 28' Harris pontoon with a 1978 Evinrude 70 hp outboard. My problem is, I cannot get the boat to pull itself off the trailer. It runs outstanding while sitting in the driveway either on the muffs, or in a barrel of water. When I take it down to the lake and back it in the water, it starts, but idles much slower, and as soon as I put it in gear and try to apply throttle, it dies. I have replaced all the fuel lines, the tank is new, the fuel line from the tank is new, I rebuilt the carburetors and made certain the floats were set to the proper height, and I rebuilt the fuel pump, the spark plugs are new, and the compression is good. I've been fighting this for some time now, and I'm getting very frustrated. The family wants to go boating! Is it possible that the incline of the ramp, along with the outboard being down is causing a fuel starvation issue? It has power trim, but it doesn't function and I don't need to raise it because it has plenty of clearance while on the trailer.

Thanks in advance, and I greatly appreciate ANY input/advice!

 

[rayodunne]

Re: 1978 Evinrude 70 hp stalls on boat ramp.

Sounds to me like your timing is not advancing as it should. You need to do a link & Sync as per your manual. Differs for alot of motors.

 

[jtexas]

Re: 1978 Evinrude 70 hp stalls on boat ramp.

I believe that if the incline was a problem, it wouldn't restart.

Agree with ray, motor dies when you throttle up indicates a spark advance problem. It will behave differently on the muffs or in a barrel than it does when it has to push the boat. The timing advance has to start before the throttles open. Make sure the timer base is moving smoothly, go through the link & sync process.

One nuther prossibility is idle set too low. With the motor running on the muffs, set the idle at about 1000 RPM, then fine tune it after launching to about 700 - 750 in gear.

I think if it was just a matter of boat too heavy and trailer too shallow, instead of dieing it would just push a lot of water without moving the boat.

It would be good if you could get it off the trailer, to see what it does in forward gear. If there's a steeper ramp in your area, I'd think about trying it, just for diagnostic purposes.

 

[BigB9000]

Re: 1978 Evinrude 70 hp stalls on boat ramp.

tilt of the ramp could cause an issue.

Im guessing you adjusted your throttle & shift cables in the driveway too?
might have to do it in the water. does it run ok with the warm up lever all the way up? then die when you lower it to put it into gear?

also, float the boat off the trailer, don't use the outboard to drag anything.

 

[BigBadStang]

Re: 1978 Evinrude 70 hp stalls on boat ramp.

It sounds like it wouldn't be a bad idea to synchronize it just to make sure. I have a manual, but I can't remember if I need any special tools. The stupid thing is 3 hours away from home at the lake with the boat. Does anyone have an idea of what tools/devices I may need?

BigB9000; My boat doesn't have a warm up lever. The OE controls have been replaced with an after market twin lever control. Maybe that's part of the problem? Doesn't the warm up lever advance/retard the timing? How long does an outboard take to warm up enough to run it under a load? I see people launch and they just start theirs up, let it run a minute and back it off the trailer.

 

[jtexas]

Re: 1978 Evinrude 70 hp stalls on boat ramp.

Flathead screwdriver is about all you'll need. 1/4" nut driver for the airbox cover if you need to check the throttle valves.

Yup, the hi-idle lever fully advances the spark, but only opens the throttles a little, I mean less than half.

My '79 needs 3 or 4 minutes before I can back off the trailer...but it's usually floating, or mostly floating where you could push it off with very little effort. If I warm it up at home on the muffs, seems to go a little faster.

 

[BigBadStang]

Re: 1978 Evinrude 70 hp stalls on boat ramp.

Flathead screwdriver is about all you'll need. 1/4" nut driver for the airbox cover if you need to check the throttle valves.

Yup, the hi-idle lever fully advances the spark, but only opens the throttles a little, I mean less than half.

My '79 needs 3 or 4 minutes before I can back off the trailer...but it's usually floating, or mostly floating where you could push it off with very little effort. If I warm it up at home on the muffs, seems to go a little faster.

Ok. Thanks! I guess I need to make sure the ignition advance isnt moving around on it's own being there is no warm up lever. I don't know how the guy disconnected it when he replaced the control...God only knows, becaue he didn't wire up my choke either. I had to put a momentary switch in and wire the choke to it...it's hard to find someone willing to put a real effort into older equipment it seems.

 

[jtexas]

Re: 1978 Evinrude 70 hp stalls on boat ramp.

yup. Rewiring an old boat is a real labor of love.

But, there's far worse ways to spend a Saturday afternoon.

The link & sync instructions include setting the WOT timing, but that's not usually necessary unless you've had the flywheel off, or somebody's been messing with the WOT stop screw. Just in case, you might want to read this thread: http://forums.iboats.com/showthread.php?t=228183 for how to set WOT timing at cranking speed. You won't see this in any manual. Obviously, you'd need a timing light.

 

[BigBadStang]

Re: 1978 Evinrude 70 hp stalls on boat ramp.

LOL...yeah, one of the previous owners didn't do us any favors. Some people shouldn't be allowed to purchase or use Scotchlok's and lamp cord!

I have a timing light and all, so I'll make sure I take it with me. I printed off the instructions that you linked for me. I appreciate the input. I know this is something goofy, because it runs too good otherwise. I'm not used to things kicking my butt like this! I usually can fix about anything, and have built many high performance car engines, and built drag cars. I will say, I am amazed that this outboard had distributorless ignition with individual coils back in the 70's! Look at how long it took for that technology to appear in cars!