1976ish 70HP Evinrude power loss.

[bradmurd]

I Have a 70HP Evinrude around 1976, there is no place to tell the model number/serial number that i could find anyways, but judging by the cowl and comparing the styles..anyways, motor ran like a top, until my cousin and i decided to hit the lake. He was driving in shallower water through a creek to get to the lake, when he hit a rock, or log, then ran through the mud and weeds. we weren't going that fast, through there until he decided to give it some juice which obviously when he hit the obstruction; the prop was wrecked, so i had a spare put it on, but now i have no power. I can start it and run the motor but at full throttle i might be going 9KM/H and it won't pick up at all. So i turned to some manual's for other johnson/evinrude outboards and i've come to a conclusion that the water pump/or water way is clogged, i just don't know for sure. There is no pee hole, or water indicator to check for, when i put my fingers by the water intake i can feel suction, and there are is a little bit of water droplets coming out of the 2 exhaust holes, but when i touch the top on the powerhead it is hot...Could i be on the right track, or is there sometihng else to look at...like i said the motor ran perfect, until my cousin hit the bottom, so i can't think its fuel, or spark plugs...even though i have checked those...This morning we took it off the dock to load it on to my trailer when we had it at 3/4 throttle and all of a sudden it took off like there was no problem...but now after slowing down we get nothing again..
we are pretty much lost. Is there anyway to clear out a possible obstruction without tearing the hole thing apart.
we took the LU off, except for the shift linkage under the cowl, because it started to rain pretty hard. If someone could point me in the right direction or confirm mine, before i take it to a dealer , that would greatly be appreciated.
thanks
-Brad

 

[bradmurd]

Re: 1976ish 70HP Evinrude power loss.

???

 

[5150abf]

Re: 1976ish 70HP Evinrude power loss.

The engine should run normally, for awhile, even if it didn't have a water pump at all, your problem has to be fuel/ignition/compression related.

Did you hit this thing hard because I am thinking you knocked a peice of junk loose and it clogged up your carb.

I had a similar problem last year, we would leave the launch and the thing would run like a scolded dog then just fall on its face and it wouldn't run above 1500 rpm.

Turned out to be high speed jets were clogged, they "looked" clean and I had to run a wire through them but it solved the problem imediately.

OR, if you ran the engine for a while after going through the mud and plugging the water intake yuou could have overheated the engine and blow the head gasket at least.

Do a compression check and I wouldn't use the motor anymore till this is figured out, you will only make whaever it is worse and may go from a minor problem to a major one.

 

[Lion hunter]

Re: 1976ish 70HP Evinrude power loss.

There should be a freeze plug on the top on the motor with the model # on it, the model # and serial number is also on the side of the transom bracket.
Your going to need that to get a carb kit and impellar.

Water pump will not effect the way it runs on a cold engine, but it does sound like you need to replace it and clean passages out. If you can't hold your hand on the head for 4-5 seconds it is to hot. either the t-stat or implellar is bad. Is there a screen over the water intake? When wa the last time the impellar was changed?

Never assume its not a fuel or spark issue. Check spark, clean carbs ect. Easy to do and rules out a lot of issues.

 

[bradmurd]

Re: 1976ish 70HP Evinrude power loss.

thank you for your input, i did check the spark on all three plugs and they all work. I will check out the carb/jets though. I took the LU off and discovered the impeller seemed to be fine with some minor cracks so i will get that replaced. Only thing i noticed was that drive pin may have dis-lodged if that were possible, because it seems to come out of the grove in the drive shaft quite easily.

I'll take a look at the carb's and do a compression test
again, thanks

 

[bradmurd]

Re: 1976ish 70HP Evinrude power loss.

turned out to be the head gasket