***UPDATE*** 1987 175 HP outboard Evinrude surging still

[rolander]

Re: 1987 175 HP outboard Evinrude surging still

Re: 1987 175 HP outboard Evinrude surging still

Last night I put the boat in the water with a 5 gallon can of premix fuel. We ran the fuel line from the motor to the tank. The good fuel line, this is stuff I put on last year, silicone 3/8 fuel line.

Anyways I noticed a difference before even starting the motor, pumped the fuel bulb and it immediatly returned to the expanded state. Before it would take a bit to expand, so right there I knew I had found a problem.

We took it out and ran it and it never missed a beat, she ran abour 5300 RPM turning my bro in laws 19 pitch OMC SS prop, getting 48 mph max speed GPS indicated. There was no surging no nothing.

However I still had a slight bog at initial hole ****. It will rev great then bog down a bit until the motor gets trimmed out. Then runs flawlessly. I am thinking maybe carbs need to be cleaned and I think I will get the gaskets and diaphrams for the fuel pump and rebuild that right away too.

So I have determined it is a fuel problem between the tank and the bulb. I guess I will be tearing some carpet and the floor out this weekend.

Thank you everyone for all your help

 

[rolander]

Re: 1987 175 HP outboard Evinrude surging still

Re: 1987 175 HP outboard Evinrude surging still

Oh I found out what a gas hog these 175 motors are. 4.5 gallons of fuel gone in half an hour running WOT. I knew they liked to drink the fuel, but holy crap didn't think it would be THAT bad LOL!!!!!

Guess I need a second job to put gas in the boat HAHA

 

[Rscardina]

Re: ***UPDATE*** 1987 175 HP outboard Evinrude surging still

thats pretty good... by my calcs you would use 17 gallons per hour at WOT...so in half an hour it should be around 8.5...ish...

pretty good to me..

 

[rolander]

Re: ***UPDATE*** 1987 175 HP outboard Evinrude surging still

thats pretty good... by my calcs you would use 17 gallons per hour at WOT...so in half an hour it should be around 8.5...ish...

pretty good to me..

Keep in mind I am used to an 83 OMC 140 horse, I could run that thing a weekend on one tank of fuel ( 30 gallons)

And it wasn't quite 4.5 gallons was probably more like 4. I put 4.5 in the can and it didn't suck it completely empty. I put probably 1/4 to 1/2 a gallon into the boat tank once it started bogging out of gas. The line wasn't all the way at the bottom of the gas can

 

[Rscardina]

Re: ***UPDATE*** 1987 175 HP outboard Evinrude surging still

i hear that.. my searay with a 170 (30 gall tank) could go all weekend and then some...

the 86 140 v4...a little different...

all i was saying is the rule of thumb calc.. HP / 10 = Gal per hour at WOT..

your numbers looked great by that calc.

 

[rolander]

Re: ***UPDATE*** 1987 175 HP outboard Evinrude surging still

So according to that calc I should be using 17.5 gallons per hour? Ouch LOL

 

[Rscardina]

Re: ***UPDATE*** 1987 175 HP outboard Evinrude surging still

Yeah I know...nasty right?.. Obviously there is play it that number..wind, current waves etc.. but yeah 17.5 GPH at WOT...

but then again..how often will you be running and gunning at WOT for an hour??...thats some serious running...

 

[rolander]

Re: ***UPDATE*** 1987 175 HP outboard Evinrude surging still

Yeah I know...nasty right?.. Obviously there is play it that number..wind, current waves etc.. but yeah 17.5 GPH at WOT...

but then again..how often will you be running and gunning at WOT for an hour??...thats some serious running...

Yea good point, the only time I have been running WOT for more then half hour at a time is now trying to diagnose this fuel problem.

I know these old OMC 6 bangers are fuel pigs. Just didn't realize how bad they actually were

 

[Rscardina]

Re: ***UPDATE*** 1987 175 HP outboard Evinrude surging still

Yea good point, the only time I have been running WOT for more then half hour at a time is now trying to diagnose this fuel problem.

I know these old OMC 6 bangers are fuel pigs. Just didn't realize how bad they actually were

it can be tough..i like to think i know what i am taking about..and when i overlook something stupid..well, man do i feel stupid.

to help in solving any fuel issues, i have always used a seperate small tank as a test subject, with new or good hoses, etc.. it she cranks on that..then you know where to look.

what i am learning now is the VRO doesnt like air..so she spits more oil, runs bad etc.. I have ben replacing fuel lines like crazy..and getting the good hose connectors..

can you say needle in a haystack!?...can drive you crazy..

 

[rolander]

Re: ***UPDATE*** 1987 175 HP outboard Evinrude surging still

it can be tough..i like to think i know what i am taking about..and when i overlook something stupid..well, man do i feel stupid.

to help in solving any fuel issues, i have always used a seperate small tank as a test subject, with new or good hoses, etc.. it she cranks on that..then you know where to look.

what i am learning now is the VRO doesnt like air..so she spits more oil, runs bad etc.. I have ben replacing fuel lines like crazy..and getting the good hose connectors..

can you say needle in a haystack!?...can drive you crazy..

Yea your not kidding man, I get to start that now, new fittings in the tank, fuel line, etc etc, probably be hooking my VRO back up and see if it works properly now that I know i have a fuel issue rather then an oil issue.

The small tank worked great, she cranked like the first day I had it out. 48 MPH GPS indicated on that heavy old 18 foot frankencraft.

 

[Rscardina]

Re: ***UPDATE*** 1987 175 HP outboard Evinrude surging still

Yea your not kidding man, I get to start that now, new fittings in the tank, fuel line, etc etc, probably be hooking my VRO back up and see if it works properly now that I know i have a fuel issue rather then an oil issue.

The small tank worked great, she cranked like the first day I had it out. 48 MPH GPS indicated on that heavy old 18 foot frankencraft.

Lessoned learned my friend... seems eveytime we have a problem we go after the big ticket items.. an air leak?? really?...no can't be..let me buy a new powerpack for 150..that'll fix it!..Errr..PLEASE TRY AGAIN...

I rebuilt my carbs..rebuilt my vro.. spent about 180 bucks to still have issues..once that was done I got 4 new coils and a powerpack...hmmm..still not right?.. well whats left...a .357 slug directed at the block?..ALMOST!

in the end..its the little things that can cause major headaches..but we overlook it as impossible..

I should have been a boat mechanic!! Cant imagine how much money has been spent fxing issues that the general public dismisses...

 

[Cofe]

Re: ***UPDATE*** 1987 175 HP outboard Evinrude surging still

Wow what a lot of reading.
Just to suggest that after all that over/oiling/dogging action, it would be advantageous to run some seafoam for a tank.......other wise "deboogger the motor"

 

[Sir Robin]

Re: ***UPDATE*** 1987 175 HP outboard Evinrude surging still

Is it not wonderful to find a problem that's NOT motor related

 

[Cofe]

Re: ***UPDATE*** 1987 175 HP outboard Evinrude surging still

Not...Pravda France

 

[rolander]

Re: ***UPDATE*** 1987 175 HP outboard Evinrude surging still

Wow what a lot of reading.
Just to suggest that after all that over/oiling/dogging action, it would be advantageous to run some seafoam for a tank.......other wise "debugger the motor"

I did that already, I actually did the decarbing method, can of seafoam to a gallon of fuel run for 15 minutes sit for 15 then run again for 15.

 

[Cofe]

Re: ***UPDATE*** 1987 175 HP outboard Evinrude surging still

Great, glad you are on top of taking care of your motor......Best of Fishin....

 

[rolander]

Re: ***UPDATE*** 1987 175 HP outboard Evinrude surging still

Is it not wonderful to find a problem that's NOT motor related

It's great, I knew it wasn't a "major" problem with the motor, but figured it could have need VRO related, or fuel, or ignition. Which can get spendy too.

Thanks to the help of everyone here I found it and should be a pretty inexpensive repair.

 

[rolander]

Re: ***UPDATE*** 1987 175 HP outboard Evinrude surging still

Great, glad you are on top of taking care of your motor......Best of Fishin....

Thanks man, yea the carbs and fuel pump are getting done next just as some general maintenence. 87 engine is probably in need of a good carb cleaning and sync.

 

[jonesg]

Re: ***UPDATE*** 1987 175 HP outboard Evinrude surging still

alls well that ends well.
Knock out the anti syphon valve ball bearing and let it free flow fuel.
Remove and clean the fuel pickup etc, clean tank, install water seperator...its a constant chant here.

 

[forty5goingon65]

Re: ***UPDATE*** 1987 175 HP outboard Evinrude surging still

jonesg is right you have a air leak somewhere in theroey think about it a carburater sucks more air than gas but it has to be the right meassure if you suck more air it will overreeve and also suck alot of gas