1st test run.

[evinrude bayliner]

I recently purchased a 70s model 85hp v4 evinrude outboard. The motor has been sitting for a few years. My guess is the last time it was run was in 2002. I changed the plugs, checked the compression, replaced the fuel filter,water pump impellar, thermostat and changed the lower unit oil. I took the boat to the lake this past weekend twice. The motor ran great all day saturday. On Sunday as the day was whinding down we were cruising at WOT when suddenly the motor stalled. It fired right back up and we cruised another twenty minutes at WOT when it stalled again. When I fired the motor up again to get back to the dock it would not start without using the choke. I also noticed that the motor uses alot of gas. It burns about 1 gallon at Wot in about 15min. This is a 17 foot bow rider with 3 people. Does this amount of fuel being burned sound right. The motor idles fine at all rpms and does not surge at all. What else should I look for that could cause this stalling problem?
Should the carbs be check out? Any info would be a great help.

 

[tashasdaddy]

Re: 1st test run.

the rule of thumb for fuel comsuption per hour, is move the decimal in the HP. to the left 1 place. 85hp 8.5 gallons per hour. the 70's were known to be gas hungry, but not that bad. better check for a fuel leak.

 

[Texasmark]

Re: 1st test run.

I'm going to guess your carb float is sticking shut due to varnish in the carbs.

Might try a decarb (archives) and if that doesn't work redo the carbs first.

Check the squeeze bulb the next time you are out and if it dies, is the bulb puffy or collapsed when it does. If puffy your fuel starvation may then be your water pump. If collapsed your tank is not supplying proper fuel to the engine caused by no vent, bad bulb, clogged tank strainer, clogged fuel line with goo caused by alcohol absorbing moisture and making a gooey blob.

My 2c

Mark

 

[Willyclay]

Re: 1st test run.

While you do not say your boat is fiberglass, I am guessing it is because you identified it as a "bow rider" design. Bow riders are usually heavier than other designs of equal length such as vee-hulls and modified v's. More weight means more gph. I had the personal experience of trying my 1959 Johnson 35HP on three different boats and got drastically different results. On a 15ft Glastron semi-v hull, it would pull one adult water skier from a deep-water start. On a 16 Glaspar Avalon with round chines and a deep keel, it would plane the boat easily. On a 15ft BOW RIDER, it struggled to get on plane and used lots of gas! FYI, props can make a big difference in performance. Mercury's website has a nice prop selection model that can give you some help. Use the features that let you insert estimated weight instead of using generic weights for the various designs in the selection. Also, it is important to know that horsepower today is measured differently on outboard motors than it was before 1985. Today it is measured at the prop shaft and that is generally 12-15 percent less than the "good old days" when they measured it at the powerhead or sometimes just assigned it a value! Good luck with your boat and keep us posted on your efforts.