74 Johnson 85hp carb rebuild and more...

Hello all,

I am in need of some help / information and I am hoping you guys can help. I have a 74 Glastron v156 with a Johnson 85hp on it. The model is 85ESL74. Motor has run great over its lifespan, but this year it is telling me it needs work. The 1st time I took it out this year it started up fairly good. 2nd time it was real good. 3rd time I took it out it was a bear to start... I notice that there is gas inside (under) the hood, looks like it is seeping out of one of the carbs.

I know that the carbs were never messed with (to my Dad's knowledge, was his boat since new in 74). Where can I find parts for this thing? I'd like to change the floats, needles, gaskets, and whatever else you would recommend. I am not sure if the hard starting has to do with the gas leak, but I'd think that COULD play into it. Also, when I go wide open from a stop I get a hiccup, then she takes off. Sometimes it loads up pretty bad when doing a sudden wide open throttle.

Also, what about the fuel filter? Where can I find that? I'm looking for recommendations and how deep I'll be if I do this myself. I've worked on snowmobile and lawnmower carbs before so they don't scare me. I also have the 74 service manual for this specific motor.

Thanks in advance!
-Bob

Re: 74 Johnson 85hp carb rebuild and more...

Bob, i would start at the basics, before spending $$$. do a compression and spark check. i would like to see compression over 100 psi, and more important, with in 10% of each other. spark should jump, atleast 1/2 inch. if all this is good, then i would do the carb rebuild, and replace the plugs. here's some info.

http://forums.iboats.com/showthread.php?t=244013
you need a kit for each carb http://www.iboats.com/mall/partfind...gd_poid=109334&gd_row=59&**********=503579370
Champion Plugs 85hp 1973 - 1980 QL77JC4 gapped.030

Re: 74 Johnson 85hp carb rebuild and more...

The aftermarket kits do not contain the floats for your carburetors. Considering the cost of the floats, the OEM kits are a better buy and you would have to buy the floats from the dealer anyway to complete the work. If your father is correct, the floats are 34 years old - replacement is a good idea.

The motors did not come with fuel filters of any kind but did have a screen in the fuel pump that does next to nothing.

A full-sized water separating fuel filter would be a really good idea. You need a fixed mounting position close to and higher than the tank because the filters work on gravity and should not be tilted.