75 OB OK no wake speed, dies out any faster

[75Mariner]

Help! Bought a 14 ft boat with a Mariner 1984 75 HP powertrim 4 cylender outboard.After you pump the bulb a bunch or pick up the gas tank higher to get it running it -idles great.Then if you throw it into gear real quick it'll run at a steady no wake speed. If you try to go any faster it dies out. I put new plugs in it. Same problem. Took it to a shop and they adjusted the carb and put another set of new plugs in it for $140. It runs just like it did before I took it there. I've ordered a manual and want to try and fix it myself. The boat wasn't in the water for a few years but the owners said they started it every year with muffs on it and put on new fuel line. The gas tank is pretty old but put new gas/oil in it. Thanks!!

 

[75Mariner]

Re: 75 OB OK no wake speed, dies out any faster

Oh yeah. I am definately a cadet here! I've been reading posts for awhile and wonder if it is the fuel filter (I hope) or fuel pump? Is this what I read about fuel starvation in another post? What's the best/fastest website to order parts from? I'll quit talking to myself now.

 

[CharlieB]

Re: 75 OB OK no wake speed, dies out any faster

You still need to determine if it is caused by a weak spark or if it is dirty carbs.

Test spark, if good then clean carbs.

 

[dlplost]

Re: 75 OB OK no wake speed, dies out any faster

TEST..have someone squeeze the bulb when you try to go faster, if it helps,
put a rebuild kit in your fuel pump...

 

[SeaKaye12]

Re: 75 OB OK no wake speed, dies out any faster

So you're out there cruisin' along; holding the gas tank up in the air? Good thing you can't go very fast

Seriously; you mustn't have very much gas in there if you can hold it up like that.

Your squeeze bulb should take maybe 4-6 squeezes and then should get hard, and it should stay hard. Have you removed the cowl to check if you have a fuel leak somewhere? All connections must be tight as to not allow any fuel or air to leak in/out. Check or replace any fuel filters or water separators that might be present in an effort to eliminate sources of restriction or leakage.

I've also heard of people squirting a little pre-mix (50:1) fuel into each carb while it's running to see if it is a fuel starvation problem.

Then; assuming that your spark checks out OK your next step would be to clean the carbs and do a lync-n-synch for the timing.

My guess though is that you have a fuel leak somewhere.

Good luck, Chuck

 

[75Mariner]

Re: 75 OB OK no wake speed, dies out any faster

This is great! Ordered a manual after my post- Thanks much guys- I've got a place to start now. Let you all know how it goes.Please keep an eye out for me , I may need to holler in the process.
Lisa D

 

[75Mariner]

Re: 75 OB OK no wake speed, dies out any faster

Anyone know what size fuel line goes into the 75 HP Mariner OB 1984? The one I bought from the marine store won't push in all the way so I can't twist it. I think they sold me the wrong size maybe?

Thanks!