1980 johnson 70hp bogging

[walleyem]

i have a 1980 70Hp johnson VRO. it idles fine but when you start to hit the throttle it starts to bog out, there fore we have to prime it with the key prime and then it will run but it wont run full speed it only runs about 28mph. its on a 16ft aluminum boat it should do about 40mph. we just redid the carbs. people are telling me its the fuel injectors. i have no idea i need help.

 

[npd4432]

Re: 1980 johnson 70hp bogging

First, please post the model number of your motor. A 1980 Johnson 70hp does not have VRO. The key is not a primer but a choke. Your motor does not have fuel injectors if it in fact is a 1980 Johnson 70hp. If you just redid the carbs, what did you do to them?? Did you clean the main jets with a small piece of brass wire?? Did you set the floats correctly??
Is your fuel tank properly vented? Does your primer ball on the fuel line stay hard or does it collapse? It does seem as if you have a fuel restriction problem or some type of carb blockage. But you have to be sure of some of the things I have mentioned above to get a good starting point to eliminate the things that are good.

 

[mikesea]

Re: 1980 johnson 70hp bogging

Wally,I agree that your problem seems to be fuel related.But.Im curious as to the help you have been getting up to now.As said a 1980 wont be VRO,wouldnt be fuel injected and .As for carbs.When they are dirty ,the require total disassembly.There are small passages that get plugged from old fuel/oil varnishing.As well as the jets.You need to have them soak in a carb cleaning solution.Depending on how bad they are will dictate if you need rebuild kits.The needle and seats can get bal ,gaskets often dry up,you should pull any plugs for the cleaning and the replacements come in the kits.You also mention the primer .Primers provide raw fuel to be squierted into the manifold .This is in lieu of the older butterfly choke.A 1980 engine would have a butterfly choke system,it would operate with the key in the same fashion.I m curious if its possible your engine has a new cowl/cover that might say VRO ,or maybe you just have the yr wrong.Hope the info helps.If not ,come back ,try and find any identifyinf info you can