1984 90 HP Evinrude Question

[djw52566]

I posted previously about a starting issue with my 1984 90 HP Evinrude, but I've got a new problem. The previous problem was solved by cleaning the carburetors. I also found that the gas tank on the boat had quite a bit of water in it. I removed all of the old gas, removed the sending unit and ensured that every bit of old gas and water was out of the boat.

Here's the new issue.

It starts but does so very hard. Once I've got it started it seems to run just fine when you have it going fast. But when going slow it runs rough and it will die on me and when it does sometimes it takes time to get it started again. I noticed that when running slow that the primer bulb becomes soft. It's like you haven't primed it enough. I've squeezed the bulb and sometimes that seems to keep it running but not always.

I've also noticed that when I have it going slow that sometimes it will actually surge, that is it will pick up a little speed without touching anything.

Any ideas?

 

[Daviet]

Re: 1984 90 HP Evinrude Question

Have you checked the spark and compression?

 

[2timer]

Re: 1984 90 HP Evinrude Question

You may a loose/faulty connection in the fuel supply hose somewhere. Maybe at the primer bulb or the connector at the engine. When she is running slow there may not be enough vacume to overcome the excess air intake. The surge may come when it overcomes the excess air.
Just a thought. I had similar issues with my Merc kicker. Runs great now that the connector has been replaced. Good luck

 

[fishinmedic]

Re: 1984 90 HP Evinrude Question

I've got an 86 60, some of the same problems. Did you rebuild the carbs? or just clean them. I just rebuilt mine, turns out that it really isn't that hard. Just like the video somewhere on here says, you spend more time getting them off than actually doing the work. FYI, it you do rebuild, don't forget to order a new air intake gasket. Following the rebuild, I won't say that it runs like new (it never will), but I will say that my starting problems (hot and cold) and my slow speed issue was gone.

 

[reddogg]

Re: 1984 90 HP Evinrude Question

X2 on the getting air into your lines reply, make sure all connections are tight. Also might indicate a fuel pump problem. If you have the pulse type fuel pumps they are easy and cheap to rebuild, the VRO type are a pain and more expensive. Here's a tip- install a glass fuel filter/w replaceable elements in a horizontol position inside the engine cowling, this allows you to see the fuel flow and to see if any crap is getting past your main fuel filters.

Red

 

[fishinmedic]

Re: 1984 90 HP Evinrude Question

Also forgot to add, just checked this again and noticed people talking about air. Check your connections to your carbs. Mine were extremely loose, no clamps on them, when I was taking it all apart for the rebuild I could freely spin the hoses along the fuel intake nipples. A pain to get off, but still that loose? they had to be letting air in.

 

[jayyyy]

Re: 1984 90 HP Evinrude Question

X2 on the getting air into your lines reply, make sure all connections are tight. Also might indicate a fuel pump problem. If you have the pulse type fuel pumps they are easy and cheap to rebuild, the VRO type are a pain and more expensive. Here's a tip- install a glass fuel filter/w replaceable elements in a horizontol position inside the engine cowling, this allows you to see the fuel flow and to see if any crap is getting past your main fuel filters.

Red

X2 Good advice