1976 evinrude 70 runs good at idle and high speed but bogs down in transisition

The coverplate for the carburators has been missing, could this be the problem with the apparent too lean mixture in the transition from idle in gear and high speed in gear? This engine runs great at idle and high speed but the engine bogs down in the transisition unless I choke it a little in the mid range.

Re: 1976 evinrude 70 runs good at idle and high speed but bogs down in transisition

If it picks up if you choke it a little, it sounds like it's time to overhaul the carbs.

Re: 1976 evinrude 70 runs good at idle and high speed but bogs down in transisition

you guys were talking about this a year ago and never posted a solution to your problem. I have the same issue and suspect the carbs. what was your resolution?

Re: 1976 evinrude 70 runs good at idle and high speed but bogs down in transisition

This was hazelheckler's first post.
You should start a new post giving your model number.
I would suspect that you also have carb problems if it works if you choke it a little.

Re: 1976 evinrude 70 runs good at idle and high speed but bogs down in transisition

hazelheckler said:

The coverplate for the carburators has been missing, could this be the problem with the apparent too lean mixture in the transition from idle in gear and high speed in gear? This engine runs great at idle and high speed but the engine bogs down in the transisition unless I choke it a little in the mid range.

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Oops, I guess I didn't make my self clear,, What effect would running this engine with out the coverplate that covers the 3 carbs and has a central inlet for the 3 carbs have on this engines performance? I got this motor with this part missing. has anyone run this model engine in the water and noticed a preformance problem, or is this part there for no good reason?

again this motor runs great at lower rpm and at high speed. I have replaced everything in the carbs except for the jets. the jets and all passageways are clear. The tank and hose is new.

Thanks,,,

Re: 1976 evinrude 70 runs good at idle and high speed but bogs down in transisition

You will not notice any difference in performance if the air silencer is not there. You will notice a little more noise with it not there.

Re: 1976 evinrude 70 runs good at idle and high speed but bogs down in transisition

What about tuning the carbs to run just a little richer? Wouldn't that help bring out the the mid-range?
J

Re: 1976 evinrude 70 runs good at idle and high speed but bogs down in transisition

I believe there was a service bulletin out on a modifacation you can make to cure this prob for that yr model. If I can find it I'll post back with it. Somebody else may chime in with it.

Re: 1976 evinrude 70 runs good at idle and high speed but bogs down in transisition

First thing to do is look for an X stamped on the top of each carb. If it's got it the carb has been modified. The service bulletin was 1429 dated Sept 1976. An old time Evin or John dlr should have it.

Re: 1976 evinrude 70 runs good at idle and high speed but bogs down in transisition

boobie said:

First thing to do is look for an X stamped on the top of each carb. If it's got it the carb has been modified. The service bulletin was 1429 dated Sept 1976. An old time Evin or John dlr should have it.

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The Carbs don't have an x stamped on them,, do you know anyone that i might get a copy of the bulletin from?

Thanks,,,hecklers@peoplepc.com is my email if anyone has it

Re: 1976 evinrude 70 runs good at idle and high speed but bogs down in transisition

http://forums.iboats.com/johnson-evinrude-outboards/service-bulletin-1429-evinrude-82693.html

Re: 1976 evinrude 70 runs good at idle and high speed but bogs down in transisition

The carbs all 3 had no x's on them and I ordered the drills, plugs, and jets. Worked perfectly this summer in virginia,,, Its run better than it ever has,,, Thanks for the help,,,,,Mike

Re: 1976 evinrude 70 runs good at idle and high speed but bogs down in transisition

Found the problem today, when I put the carb back together i didn't notice that the bellcrank/lever attached to the secondaries that raise and lower the 2 metering rods, and the two rods were missing, works fine now

Re: 1976 evinrude 70 runs good at idle and high speed but bogs down in transisition

Gett the air silencer cover as well for your engine, because ofcourse it makes a difference to its running sweet.
do you serously think that omc would of spent a fortune in designing it, making it and then fitting it,plus making
gaskets for it and the screws?
all this cost man hours and time = money,plus the cost of the parts.
omc would of probably spent a an absolute fortune in the making of all this stuff, and if they could of got away without it
then no chance of fitting it for sure.
think how many engines omc have produced, and lets say just $10 in time and money for each engines airbox ????
i have not a clue how many engine omc produced with air boxes in total but i reckon its millions.
the airbox is not just to keep it quiet,its tuned to deliver the right amount of air for the carbs to operate at their best.

so if i were you i would get the original air box, they can be found cheap enough on evil bay.


phill

Re: 1976 evinrude 70 runs good at idle and high speed but bogs down in transisition

hazelheckler said:

Found the problem today, when I put the carb back together i didn't notice that the bellcrank/lever attached to the secondaries that raise and lower the 2 metering rods, and the two rods were missing, works fine now

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Metering rods and secondaries? Sounds like your talking about a Rochester q-jet lol, not erude 70hp carbs

Re: 1976 evinrude 70 runs good at idle and high speed but bogs down in transisition

I was ,,, thats my second boat, i don't know how it got here,, must have been my mistake,,, sorry