1992 40 HP Mercury problem

[fisher]

Was out on Lake Simcoe last week and my 1992 40 HP Merc was bogging down - both at low speed and high speed.

 

When starting out, it seemed as though I was dragging a 1000 lb anchor. When I finally got it up to some sort of plane (which took a long time), it was not reaching it's normal top speed. A couple of times it just died on me at the higher speed. At idle/slow troll, it too would die.

 

I don't think it's the fuel line, as it would start up again without any priming of the bulb, etc...but I would need to choke it first (which I normally did when the motor worked fine).

 

Is it the carbs - maybe gummed up? I have had the motor for about 6 years and never got them cleaned before.

 

I looked up older posts and saw that MoriaRiverMan had a similar issue - never did see what the resolution was.

 

Anyone have an idea if my totally inexperienced diagnosis may be correct? Can you recommend a mechanic to look at it.

 

Are there any freelance mechanics willing to come see it on their off hours - obviously I'd be willing to pay for their time/work? I tried calling Leisure Marine in Woodbridge (near where I live) but they won't look at it for at least 2-3weeks. I need to get this fixed sooner than then.

 

Thanks.

[Sinker]

Its starving for fuel one way or another. Could be fuel line, carb, fuel filter.....etc.

 

Sinker

[raysfish2005]

Hmmmm sounds like some fuel was left in the carb and is clogging up the jets, remove and clean out carbs and you should be good to go

[muskymike]

Sounds like a carb problem. You didnt use old gas did you?

[fisher]

Hmmmm sounds like some fuel was left in the carb and is clogging up the jets, remove and clean out carbs and you should be good to go

 

 

Is this something someone could do themselves? It sounds simple...but then again don't most things? I mean, at first glance, how difficult does being married sound ?

[fisher]

Sounds like a carb problem. You didnt use old gas did you?

 

 

I stabilized the gas tank over the winter using a fuel stabilizer (as I have done for the last 6 years) and used it this spring. This was my 3rd trip out and now am experiencing the bogging issue. The previous year's gas has already been consumed.

 

I read that stabilizing the gas over winter was the proper thing to do and that it would be okay to use in the spring - is that not good advice?

[fisher]

I have been researching cleaning carbs on the net and found many references to using SeaFoam/Merc Carb Cleaner as a first step in trying to resolve the issue I am having.

 

Does anyone have an opinion/eperience on this proposed solution?

[bushart]

I had a similiar problem with my 50 merc---I had crud in the fuel filter that when it called for more fuel as in acceleration it would suck the crud up quicker to the port---changed the filter (cheap fix) and was done.

 

This year I've also had some fuel line issues with my tank hose but it caused different problems--sucking air

 

Actually my filter issue was when my motor was nearly new and I was getting my fuel on a lake marina where I believe their tank was contaminated--as I have a plastic built in tank and my filter had rust particles in it---probably not from my new motor

[perodimi]

This may be an obvious question but if it has a portable tank, did you have the fuel vent wide open? If not, the engine would be struggling to draw the fuel out of the tank. If it's a fixed tank, check if that vent is obstructed.

 

A simple thing to check before taking the carb apart?

 

Peter

[Sinker]

I use the seafoam/merc power tuner to de-carbon the motor. It just cleans out any carbon build up in the cylinders and exaust.

 

Your problem sounds like a fuel issue.

 

If the engine worked fine the other two times you had it out this year, I'd say you picked up some crud from the bottom of your gas tank,and its clogged a jet in the carb. Did you check the fuel filter? It may be gummed up, and restricting the fuel flow to the carb. If that's clear, its something in the carb that's blocked. I don't touch carbs, but there might be someone else here than can help you out.

 

I have a 93 mariner......essentially the same engine......I change the filter every spring, just because its easy. Never had a carb problem with it though.....

 

Sinker

[fisher]

This may be an obvious question but if it has a portable tank, did you have the fuel vent wide open? If not, the engine would be struggling to draw the fuel out of the tank. If it's a fixed tank, check if that vent is obstructed.

 

A simple thing to check before taking the carb apart?

 

Peter

 

 

I checked the vent on the tank and it was open - and the bulb was nice and firm. I also had replaced the fuel filter - because I thought the same thing- cheap, inexpensive part. I tried again, and still bogging.

[Sinker]

prime the engine with the bulb on the fuel line, start the motor, and take off the fuel line. See if it still bogs with the line off.

 

I still think your carbs are blocked.

 

Sinker

[fisher]

I use the seafoam/merc power tuner to de-carbon the motor. It just cleans out any carbon build up in the cylinders and exaust.

 

Your problem sounds like a fuel issue.

 

If the engine worked fine the other two times you had it out this year, I'd say you picked up some crud from the bottom of your gas tank,and its clogged a jet in the carb. Did you check the fuel filter? It may be gummed up, and restricting the fuel flow to the carb. If that's clear, its something in the carb that's blocked. I don't touch carbs, but there might be someone else here than can help you out.

 

I have a 93 mariner......essentially the same engine......I change the filter every spring, just because its easy. Never had a carb problem with it though.....

 

Sinker

 

 

I change the filter every spring as well - changed it again this weekend after the issue just in case it was a dud - but still same issue.

[fisher]

Great news - Discount RV and Marine on Keele St in Maple told me to drop the boat off tonight and that they will be able to look at my boat in about a week.

 

If it indeed is the carbs - what would be the approx price to clean out the carbs (I think there are two) on my 1992 40 horsepower Merc?

[cranks bait]

Had this problem with a 9.9 at the cottage. Turned out the seal was toast one the block. Had it redone and all was good.

[misfish]

Your needle valve could also be sticking.Just a thought. I went through this two years ago. Gunk build up.

[captgar]

had a similar problem bogging down on a 50hp, and stalling out, turned out to be the thermostat, it was sticking and overheating the computer then limits the revs to prevent real damage.

[Garry2Rs]

When was the last time the plugs were changed?

[Sinker]

I also had similar problems with mine last fall. I though for sure it was a fuel problem, but it turned out to be the head gasket. It was less then $200 to get a new one put in, and I had it back in 2 days.

 

Check your plugs. Mine had one plug that was wet......you could tell it was oil mixed with water, it had that milky colour on the plug.

 

Just a thought......

 

Sinker

[MoriaRiverMan]

I got my issue fixed.......

 

I installed a carb kit first...........installed new plugs

 

Problem was still the same

 

Did compression check and both were even at 123-125

 

Then my dad was down for the weekend and told me it sounded like it was starving for fuel........... well ajusted the needle setting about 1/4 turn and now runs like a champ

 

previous owner had motor in for same issue and got a 800$ bill and still had problem What a 1/4 turn can do

[fisher]

Well I brought it into the Marina last night and now it is up to them. They figure they should be able to look at it within a week.

[wmshaw]

I have had a similar problem and it was related to water in the gas. Check you gas to make sure there is no water in it.

 

Bill

[POLLIWOGG]

First thing I do to fix a motor is tell them the gas is no good, drain it out and put it in my truck cause it will burn anything. When that doesn't work and it never does I clean the carbs.

 

My bud had his do the same thing, when he had it wot and it bogged down, he choked it and it would take off. The main jets on these are tiny and plug up easily plug up, I cleaned the carbs and it worked good for a couple hrs. and bogged again. My bud watched me clean the carbs so he tore them down and found a dandelion seed in the jet.