Any mercriuser techs on board

[vinnimon]

My problem, the engine is dying out upon accelation under load.

 

I should tell you that the engine is totally rebuilt.You name it, its been done.2 new piston heads and con rods, new bearings and rings,new cam, lifters,pushrods.The crank was turned as well.The block welded.The head was plained and new seals and springs installed by a shop.New accell wires and a coil as well as a starter.I replaced wires that didnt pass a resistance test.

 

Now, what I did notice when the engine stalled, the slave solonoid had power on one side and not the other(just below the breaker).So I jumped the connection and it started.Never failed again.

I can run my engine all day in my driveway and throttle up with no issues.

While in the water as soon as I want to acceleraate shes stumbling and wants to stall right a way.Idling not an issue.

 

One other thing I want to add, if it sits for a while at home, Its takes a while for it to start.

 

The only thing I can see is a carburator problem,Maybe the float is stuck? Everything else checks out.

[DRIFTER_016]

Yeah, it sounds like carb or fuel pump issues. Could be the accelerator pump diaphram, H2O in the fuel, crud in the carb or weak fuel pump. Could also be a plugged filter. If it were me I would replace the filter and do a carb rebuild.

[ctdd2006]

Yeah, it sounds like carb or fuel pump issues. Could be the accelerator pump diaphram, H2O in the fuel, crud in the carb or weak fuel pump. Could also be a plugged filter. If it were me I would replace the filter and do a carb rebuild.

 

 

Check the filter. Been there done that only problem was I waited till opening walleye weekend to test it out of the yard!!!!!!

[vinnimon]

sorry I forgot to mention.I checked the pump when it happened.I got sprayed.As for the filter,I replace it 3 times in a season.I sits in a canister above the pump.The line I cracked open was on the down stream side of the filter.The pump is the same as an older gm mech pump, except the filter housing is attached to it.

So I guess I have a carb problem,Float sticking, maybe.

 

If thats the case, I found a guy that rebuilds carbs off of the 427/qew, along the queensway I think.I purchased an electric choke from him.Only if I can remember the name.HMMMMMMMM, he knows his stuff.

[irishfield]

2 barrel.. 4 barrel.. vacuum or mechanical secondaries?

[canadadude]

I had the same problem one season and it turned out to be plugged fuel line from the gas tank. I was filling the boat with jerry cans of gas and scratching off little bits of plastic off the can nozzel,These little bits eventually clogged the fuel line and would starve the engine of gas under load.I would get some gas through the line but not enough to accelerate with.

 

When my float stuck the engine would flood right out, would be real tough to start it again.It may be a carburator I'm no marine mechanic my brother is, take it to St Catharines Marina ask for Mike, he'll fix you up in no time.

Edited April 10, 2010 by canadadude

[vinnimon]

2 barrel.. 4 barrel.. vacuum or mechanical secondaries?

2 barrel,its mid to late 70s, so I have to say vacuum.There is a clear hose attached to it.Im going through the manual as we speak.I may be able to identify it.Obviosly a mech pump.

[irishfield]

I ask because the old Rochester 4 barrels with vacuums use to bog under some loads... due to vacuum issues. Thinking maybe your boat under certain loads = incorrect manifold pressure to pull the secondary in.. or a vacuum hose leak. That said...most 2 barrels don't have secondaries...

 

Partially clogged jet...

[vinnimon]

I ask because the old Rochester 4 barrels with vacuums use to bog under some loads... due to vacuum issues. Thinking maybe your boat under certain loads = incorrect manifold pressure to pull the secondary in.. or a vacuum hose leak. That said...most 2 barrels don't have secondaries...

 

Partially clogged jet...

according to pics in the manual, it may be a roch b/bc or2gc/2gv carb.I will check the tag on the carb and call dewilt honda.

Something also tells me it may be a merc carb?Dunno.I will let you know tomorrow.

[Spiel]

I ask because the old Rochester 4 barrels with vacuums use to bog under some loads... due to vacuum issues. Thinking maybe your boat under certain loads = incorrect manifold pressure to pull the secondary in.. or a vacuum hose leak. That said...most 2 barrels don't have secondaries...

 

Partially clogged jet...

 

 

 

Can you dumb it down for me a little Wayne.

 

 

[irishfield]

Mercury doesn't build carbs... just like walmart doesn't build batteries..

[vinnimon]

Mercury doesn't build carbs... just like walmart doesn't build batteries..

Thats what I thought?I recall it stamped merc.It has to be a rochester carb 2 bbl.

I recall talking to active engines in Miss.I gave them the vin of the engine for a cam and gear set.Shoot I forgot, new timing gears as well.Crank(metal), cam( fibre composite).If you know GM, then you know why the cam timing gear is composite fibre.Anyway I recall him saying rochester carb.I will take a pic after work for ya, for id and a # on the tag.

[Randy Barrett]

Sounds like dirt or gel in the fuel bowl,at idle and not under load it's not drawing enough to suck the dirt up to the jets. As soon as it's under load it draws alot more fuel and sucks the dirt up to the jets,once it stalls it fall back away allowing it to start again.

Try pulling the fuel bowl and cleaning it out,remove, check and clean the jets while your at it.

Edited April 10, 2010 by Randy Barrett

[DRIFTER_016]

I ask because the old Rochester 4 barrels with vacuums use to bog under some loads... due to vacuum issues. Thinking maybe your boat under certain loads = incorrect manifold pressure to pull the secondary in.. or a vacuum hose leak. That said...most 2 barrels don't have secondaries...

 

Partially clogged jet...

 

 

And that's why they got the nickname Quadra Bog's!!!!

[vinnimon]

Sounds like dirt or gel in the fuel bowl,at idle and not under load it's no drawing enough to suck it up to the jets. As soon as it's under load it draws alot more fuel and sucks it up to the jets,once it stalls it fall back away from the jets allowing it to start again.

Try pulling the fuel bowl and cleaning it out,pull and check and clean the jets while your at it.

Keep in mind when I said under load, It was meant while in the river or lake.On my driveway I can throttle up no problem.There is though a little hesitation if I throttle up slowly.At the same time the water pump and impeller(pick up pump(new))are working fine.Lots of pres on the outlet end of the pump.And she pees like a race horse.

[vinnimon]

And that's why they got the nickname Quadra Bog's!!!!

Quadra bogs?I heard this before with the monte carlo 305 guys.A bogging quadra jet carb?I had an 84 cutlass 305 quadra and she bogged.Actually If I recall correctly, it was the 2 barrel that had more issues.I know.

[Randy Barrett]

Keep in mind when I said under load, It was meant while in the river or lake.On my driveway I can throttle up no problem.There is though a little hesitation if I throttle up slowly.At the same time the water pump and impeller(pick up pump(new))are working fine.Lots of pres on the outlet end of the pump.And she pees like a race horse.

When it's not in the water it's not under load so not using as much fuel. I know it's not the same equipment but at the start of last winter with my snow blower I could start it up it would idle fine,go to full throttle it would run fine but as soon as I got into the snow it would die after about 5 sec.It would restart right away but just die under load. Pulled the fuel bowl and found gel in it.(had just bought the blower and don't know how long it sat with that fuel in it)Once I cleaned it out and put it back together it ran great the rest of the winter.

Edited April 10, 2010 by Randy Barrett

[OhioFisherman]

LOL quadra bog, had a 325hp 396 in a 68 camaro with a 4 barrel quadra jet on it, if the air filter got a little dirty it would bog.

[vinnimon]

When it's not in the water it's not under load so not using as much fuel. I know it's not the same equipment but at the start of last winter with my snow blower I could start it up it would idle fine,go to full throttle it would run fine but as soon as I got into the snow it would die after about 5 sec.It would restart right away but just die under load. Pulled the fuel bowl and found gel in it.(had just bought the blower and don't know how long it sat with that fuel in it)Once I cleaned it out and put it back together it ran great the rest of the winter.

Gelling is a common problem with deisels in cold temps.A snowblower is gas powered and it was pobably water that froze.If its a 2 stroke then oil and water froze upin the fuel bowl.Kinda like a slushi.No gelling or anything like that.No water in the gas at all.The tank was cleaned out entirely.

A carb prob im sure,it bogs.

[Randy Barrett]

Gelling is a common problem with deisels in cold temps.A snowblower is gas powered and it was pobably water that froze.If its a 2 stroke then oil and water froze upin the fuel bowl.Kinda like a slushi.No gelling or anything like that.No water in the gas at all.The tank was cleaned out entirely.

A carb prob im sure,it bogs.

 

Old fuel will create some gel,it wasn't water. It was meant as an example,dirt will do the same thing as I don't figure your fuel is old enough to gel. It could be someting as simple as when they had the motor apart the fuel lines were diconnected,when one of the rubber lines was reconnected a small peice of the rubber line was broken off on the inside of the connection and made it's way into the carb. It's a cheap and simple check to ,if nothing else rule it out.

 

I don't have any experince with inboards but have a fair bit of experience with older cars and trucks an alot of carb problems come down to a little bit of dirt in the carb. Just trying to help!

[vinnimon]

Old fuel will create some gel,it wasn't water. It was meant as an example,dirt will do the same thing as I don't figure your fuel is old enough to gel. It could be someting as simple as when they had the motor apart the fuel lines were diconnected,when one of the rubber lines was reconnected a small peice of the rubber line was broken off on the inside of the connection and made it's way into the carb. It's a cheap and simple check to ,if nothing else rule it out.

 

I don't have any experince with inboards but have a fair bit of experience with older cars and trucks an alot of carb problems come down to a little bit of dirt in the carb. Just trying to help!

The lines are new,except for the feed to the carb,its steel and I wire brushed it inside.I wonder,the stabilizer i put in and the foging oil down the carb.HMMMMMMM.maybe I disturbed something?Between the last time it was out(starter went)and my last outing.Stabilizer,fogging oil,maybe the carb is gummed upalittle.I know its a fuel problem.New cam and pump is good(rides on cam lobe)Delivery to carb good.Fuel and lines are clean.

Just so you know, its practically the same engine thats in a chevette.Inline 4 except its a 3 ltr engine not a 2.8ltr.

Igues its time to rebuild the carb.Dang nabbit

[Big Cliff]

The first thing I would do before you start rebuilding the carb is pressure test the fuel lines from the tank to the carb. A small air leak could easily cause the problem you are describing. System should hold 5 psi pressure. You'll need a leak down tester.

[wormdunker]

Old fuel will create some gel,it wasn't water. It was meant as an example,dirt will do the same thing as I don't figure your fuel is old enough to gel. It could be someting as simple as when they had the motor apart the fuel lines were diconnected,when one of the rubber lines was reconnected a small peice of the rubber line was broken off on the inside of the connection and made it's way into the carb. It's a cheap and simple check to ,if nothing else rule it out.

 

I don't have any experince with inboards but have a fair bit of experience with older cars and trucks an alot of carb problems come down to a little bit of dirt in the carb. Just trying to help!

[wormdunker]

I had a similar issue with my Polaris ATV. I could get it started, would idle properly but, when I tried to accelerate it would bog down - almost like running at half throttle. I was fortunate enought to have a fellow poster send me a link to a site that described (with pix) how to remove, clean & reinstall my exact carb. I removed the carb, cleaned it, checked that the float was working properly, the reinstalled it. While doing this work I also removed & cleaned the gas tank, fuel lines & installed a new fuel filter. All said & done it now runs very well. I found debris in the tank which also found it's way into the carb. Good luck!!

[Twocoda]

im going to throw this out there Vinni

 

have you considered the gimble bearing in the lower end??? if your running good at idle and under load in the driveway with no resistence then once in the water the prop resisnce to the water might be just enough to throw a failing gimble bearing out to cause probs...im not a mechanic but have had this happen to my boat