Fuel Problem

[Crosbyman]

Did you give a good shot of engine cleaner like Evinrude engine cleaner or Mercury Power tune ....some like seafoam some not ...

run it at full rpm to circulate the mix then drop rpms to idle

I know it is not as good a fix as a carb job but....it could be an easier fix.

 

[FreeBeeTony]

You need to understand that IF ( big word ) there is a blockage in a carburetor you might starve one cylinder of gasoline along with the oil !

Good point.

 

[FreeBeeTony]

Did you give a good shot of engine cleaner like Evinrude engine cleaner or Mercury Power tune ....some like seafoam some not ...

run it at full rpm to circulate the mix then drop rpms to idle

I know it is not as good a fix as a carb job but....it could be an easier fix.

I'm currently running seafoam in the gas right now.....about 1oz/gal, guess I could increase it.

 

[oldboat1]

SeaFoam is a mix of lubricants and solvents — maybe creating an overly rich oil to fuel mix, or (conversely) loosening up contaminants in your tank and running them into your combustion system.

At 1 oz SeaFoam per gallon of fuel, the change is significant and could be exacerbating operating problems you already have, or creating new ones. Introducing solvents to decarbon the engine is a different procedure.

 

[Crosbyman]

possibly.... but it sure fixed my carb problem on my snowblower
time will telI i guess

 

[FreeBeeTony]

UPDATE: I think I narrowed the problem to the Port car bank. Disconnected the lines from the Primer Solenoid 1 at a time, the 1 on the Starboard side made did not make an improvement but the Port side did. I then sprayed Gum-Out next to the intake manifold on the Port side band on the center of the engine. Definitely had an effect on the engines performance. Could I have a bad gasket in that area?
Would a compression test indicate a possible problem as I suspect?

 

[racerone]

A compression test checks piston , ring , cylinder and head gasket condition.-----A compression test in the cylinder has noting to do with crankcase compression , reed valves and crankcase gaskets.

 

[FreeBeeTony]

A compression test checks piston , ring , cylinder and head gasket condition.-----A compression test in the cylinder has noting to do with crankcase compression , reed valves and crankcase gaskets.

I am familiar w/ a compression test on a SBC.....not on a 2 stroke. I understand the intake is in the crankcase on a 2 stroke, I was wondering if a problem w/ the intake would show-up on a compression test. I did conduct a compression test: 95-110 across the 6 cylinders. How can I test the crankcase pressure or vacuum?

 

[Crosbyman]

do easy stuff first... clean the carbs and fuel distribution

 

[Chris1956]

Tony, Carb kits usually come with gaskets for the side plates on the throttle bodies. You can spray the idle passages and idle needle after removing the side plates, without removing the idle needle. So the carb synch is not disturbed.

Carb kits will come with the "spaghetti" seals for the carb base. Order the ones for the throttle bodies as well, to do a complete job.

Don't forget to blast the intermediate orifices clean while you are at it.

 

[Scott Danforth]

I'm currently running seafoam in the gas right now.....about 1oz/gal, guess I could increase it.

there is no mechanic in a can

seafoam can not unclog your carburetor

 

[Lou C]

I recall my mechanics (these were some of the best OMC mechanics around) talking about certain OMC carbs that were prone to warpage, not sure if that's the case here though.
That's one area where an inboard or I/O is simpler than a carbed outboard, I can't imagine having SIX carbs to deal with vs one! By comparison a Quadrajet or Holley is easy...
Hope you get it Tony....

 

[FreeBeeTony]

I recall my mechanics (these were some of the best OMC mechanics around) talking about certain OMC carbs that were prone to warpage, not sure if that's the case here though.
That's one area where an inboard or I/O is simpler than a carbed outboard, I can't imagine having SIX carbs to deal with vs one! By comparison a Quadrajet or Holley is easy...
Hope you get it Tony....

Thanks Lou.......this is the ONLY time I miss my SBC I/O!

 

[FreeBeeTony]

there is no mechanic in a can

seafoam can not unclog your carburetor

I agree, can't hurt to try though. I actually added the Seafoam before this problem occurred......wonder if it caused it??

 

[FreeBeeTony]

A compression test checks piston , ring , cylinder and head gasket condition.-----A compression test in the cylinder has noting to do with crankcase compression , reed valves and crankcase gaskets.

I'm still curious, is there a way to test for Vacuum of Pressure in the crankcase? I was thinking I could connet a Vacuum gauge the the nipple on the intake manifold that connects to the Primer solenoid. Should there be Vacuum there? I could compare 1 side to the other...

 

[Chris1956]

Tony, your motor is 2 cycle, so each cylinders crankcase is designed to be isolated from all others. You would need to check pressure/vacuum on each cylinders crankcase.

Gee, why not just clean your carbs?

 

[FreeBeeTony]

Tony, your motor is 2 cycle, so each cylinders crankcase is designed to be isolated from all others. You would need to check pressure/vacuum on each cylinders crankcase.

Gee, why not just clean your carbs?

I am planning on doing the carbs after I pull the boat, don't want to do it while the boat is in the water....just thought it seemed odd the way the GumOut affected the performance when sprayed next to the intake and wanted to be sure it's the carbs. I'm afraid to run it as is now.

 

[Chris1956]

The gumout sprayed on the intake components indicate an air leak. I would check the bolts on the carbs (carefully) to make sure they are tight. You do not want to crack the carb bodies.

If the air leak is small, it will have minimum impact on high speed operation. it will normally make the engine run lean at idle or low speed.

 

[Lou C]

I think that’s what my mechanics were taking about, warpage causing a vacuum leak

 

[FreeBeeTony]

The gumout sprayed on the intake components indicate an air leak. I would check the bolts on the carbs (carefully) to make sure they are tight. You do not want to crack the carb bodies.

If the air leak is small, it will have minimum impact on high speed operation. it will normally make the engine run lean at idle or low speed.

I already checked the bolts around the carbs unfortunately.....now I'm suspecting something "behind" the carbs. I'm guessing intake gaskets going bad is NOT common.