1979 115hp Evinrude...now what?

[RUHokie]

Model J115999R<br /><br />OK, I've replaced the fuel hose & primer bulb, all new interior fuel lines, rebuilt fuel pump, and removed carbs and took them to dealer where they cleaned and rebuilt them. Fresh gas, good compression (135, 135, 145, 150), good spark (NGK plugs), and new waterpump. Still has the same problem. Idles fine, but when I throttle up when in gear, it dies immediately. Not a slow, choke down die, but an immediate stop. Always restarts with no problem, but dies when you "give it the gas". When I throttle up in neutral, it seems to run fine, but I've got no tach, so I don't run it long at higher rpms. Put it in the river again today, and for the first time, it died while idling out to the channel. Wouldn't restart for about 10 minutes, almost like it's getting too much gas? No indications of fuel leak (dry under carbs and fuel pump, no fuel film floating on the water around the engine). After 10 minutes of grinding on the starter and swearing under my breath, it restarted and idled all the way back in to the dock (25 minutes). While at the dock, put the engine in neutral and throttled up, engine ran fine. I just bought this boat and motor a month ago, and the previous owner said it had sat in the shed for 2-3 years without being in the water. Said it was running fine last time out.<br /><br />What else am I missing? I have run into a brick wall here. Can anybody help?

 

[Dhadley]

Re: 1979 115hp Evinrude...now what?

First lets get the right Champion (L77JC4) plugs in it before we're looking up piston part numbers. Once we get that done lets look at jetting. If the carbs are clean and the sync & link is correct, we may have to richen up the idle circuit. Not all that uncommon on older motors. It was produced in the late 70's and calibrated for the fuel at that time. That fuel's gone.

 

[Dhadley]

Re: 1979 115hp Evinrude...now what?

Is the fuel fresh?

 

[K Hultgre]

Re: 1979 115hp Evinrude...now what?

do a link and sync. <br />Sounds like the high speed jets are not kicking in (clog'd). have you tried to choke it when accelerating.

 

[87Aggie]

Re: 1979 115hp Evinrude...now what?

Dhadley, could you be a little more specific when you suggest richening up the idle circuit?<br />RUHokie, hope I'm not stepping on any toes!

 

[Dhadley]

Re: 1979 115hp Evinrude...now what?

On some older motors, V4's in particular, they sometimes stumble on acceleration when everything is as it should be. At that point we just look at the idle jets and if they're, say #30's -- we go richer by 2-3 numbers. <br /><br />You can try to bump the choke as Kevin mentioned but with a choke it will most likely flood it. We do that with later models that have the primer system and it will help overcome a lean condition.

 

[RUHokie]

Re: 1979 115hp Evinrude...now what?

87Aggie, don't worry about stepping on toes...I'm at the point any help is welcomed!!!<br /><br />Dhadley, I've tried jumping on the throttle and I've tried sneakin' up on it. Dies both ways. Why is it revving up fine in neutral, but dying in gear? I can't figure what the difference might be. Anything to do with the timing advance?<br /><br />Kevin, it really doesn't give me a chance to choke it...it dies real quick, like somebody cut the switch off. What if I held the choke in and then tried to accelerate? Maybe I'll try that next trip to the river, but right now, I'm leaning towards taking it to somebody else. I hate to, because that's the same as giving up, and that goes against my grain.<br /><br />Anybody with fresh ideas?<br /><br /><br />Got 2-6 gallon tanks, both old. Cleaned out both tanks and filled both with fresh 87 octane 4 weeks ago and 50-1 mix, so fuel is very fresh (over $2 gallon!).

 

[RUHokie]

Re: 1979 115hp Evinrude...now what?

Dhadley, do you really think it could be as simple as changing plugs? I know that Champions run cooler, but how could that affect my situation? I'm willin' to try anything at this point, but I really don't see how that will help my particular case.

 

[fireman57]

Re: 1979 115hp Evinrude...now what?

Those engines were built for Champion plugs. Son't know that it will fix it but at least you can eliminate that as part of the problem.

 

[RUHokie]

Re: 1979 115hp Evinrude...now what?

Thanks Fireman57, will pick up Champion plugs tommorrow and give them a try. I feel like my problem HAS to be a timing problem, because the motor runs too good when not under load. Any other thoughts?

 

[Dhadley]

Re: 1979 115hp Evinrude...now what?

It'll rev in neutral because theres no load. Look at the linkage under the flywheel. If it moves, your timing is advancing. <br /><br />The plugs may or may not cure it but you could be looking at bigger problems soon. Also -- use that gas ASAP. 4 week old fuel is not fresh. Its not too old yet but getting there.

 

[fireman57]

Re: 1979 115hp Evinrude...now what?

Dhadley, I know that the additives that used to be in our gas are not there anymore to keep it fresh. But four weeks doesn't seem that old to me. How long does it take from being refined to our vehicles tank? I'm not familiar with RUH's engine but is sounds like he may not be running on all cylinders and a spark test may be in order. But I'm interested in the fuel issue. Seems like it should be alright for at least a couple on months. I'm curious and would like your thoughts on why it gets "old" that quick.

 

[RUHokie]

Re: 1979 115hp Evinrude...now what?

Good Morning Dhadley, et al!<br />Headed out this morning for a quick run to town (22 miles) to get Champions. I did go check the timing advance last night. I ran throttle all the way forward (key off) and then pulled back on timing advance linkage. Pulled back easy and snapped back forward when I released it. I thought maybe there was some "goo" from under the flywheel keeping the timing from advancing properly, but seems to be free so I don't think that is my problem.<br />On another note, the fuel hose and primer bulb assembly I just bought MIGHT be defective. When I pump up the hose without it being connected on either end, the bulb gets rock hard. When I hook one end to the engine, the bulb will collapse and not refill. But when I connect the other end to the fuel tank, I can pump it up "sort of firm" and then I can hear fuel or air being pushed around in the fuel tank while I'm pumping the primer bulb. The bulb is "spongy", not firm like when I pump it when it's no attached at either end. I suspect a faulty check valve in the bulb, even though this is a new hose assembly. I don't really think that this is the cause of my problem, because the engine was acting the same with the old hose and bulb. But at least the old bulb would pump up firm.<br /><br />Any more ideas before I head off to town?