Johnson 1998 150 Ocean Runner Air Leak?

[Riley C]

Hi Guys,

I have serviced my recently purchased 98 150 Ocean Runner (J150EXECD). I'm having issues with excessive oil at idle.

Meter has 700 hours. Although doesn't look like it.

Works have just been completed.

1. New fuel lines, water separator filter. Previously had 5/16 now 3/8 lines.
2. Carbs pulled down and new service kits on all six. Needles had some wear.
3. Gear oil replaced and new T&T oil added.
4. New Champion Plugs
5. Decarb engine
6. Cleaned out VRO tank and replaced really old oil. Purged new oil through line to VRO. (Alot of gunk came out)

Compression when warm gives 110psi.

Not having any issues with idle rough/knocking/lean sneeze or anything, it idles at 850 in the water. In the water it get 5300 at wot (3/4 trim out on gauge).

My biggest issue is I can't start her up in the driveway as it excessively Smokey. Neighbours will shoot me!

One thing I noticed was the primer bulb does go down after an hour. My in-floor tank vent is working.

Could the Vapour separator cause any of this ( I didn't replace the needle in it) or are my lines getting a leak somewhere?

What is the proper method for a air leak test?

Carb bowls are not overflowing, fuel doesn't really leak from anywhere unless fully tilted up while travelling.

Are there likely culprits to check if it's not the lines? The filter at the fuel housing is old but no crack in it, I replaced the O rings.

I go through oil like I own OPEC. 3lts used mostly at 3500-WOT over 100lts of fuel.

I don't get any warnings. Engine reaches temp well on the gauge, thermos kick in.

Other than that she runs good as gold.

Cheers.

 

[jakedaawg]

Plumb in a section of clear fuel line just before the VRO. Tee in a vacuum guage. Find your fuel restriction sensor, is it black or grey? Look in manual to determine how many in/hg you should have based on color of the sensor. 3-5 or 4-6 but dont quote me on that, look it up. If you have a bad reading find the fuel restriction. If you see bubbles in the clear section find the air leak. Either condition can lead to over oiling condition. These motors do smoke quite a bit on muffs.

Should you pass both tests above do the oil consumption test outlined in the manual. Good luck.

 

[Riley C]

Plumb in a section of clear fuel line just before the VRO. Tee in a vacuum guage. Find your fuel restriction sensor, is it black or grey? Look in manual to determine how many in/hg you should have based on color of the sensor. 3-5 or 4-6 but dont quote me on that, look it up. If you have a bad reading find the fuel restriction. If you see bubbles in the clear section find the air leak. Either condition can lead to over oiling condition. These motors do smoke quite a bit on muffs.

Should you pass both tests above do the oil consumption test outlined in the manual. Good luck.

Thanks for the reply!

I haven’t done a vacuum test yet. I will get a gauge and clear hose tomorrow. Is it as simple as tee in between the hose and the engine connection? The gauge wil read off syphon from the fuel pump?

Glad I bought the omc manual straight up.

 

[jakedaawg]

You want the clear hose with the guage teed in after the cowl connection as that's a likely culprit for a air leak. The manual explains it in acceptable detail.

 

[Riley C]

You want the clear hose with the guage teed in after the cowl connection as that's a likely culprit for a air leak. The manual explains it in acceptable detail.

Going over the manual, I hooked up the gauge after warming her up. For some reason I don't get a reading at all, I'm scared revving her in a test bucket over 2500. Definitely air in the line though.

Looking at all my hoses etc. I have replaced the spring clamp at the cowl barbs with a hose clamp (Can you use hose clamps?). This was moving with the hose, suspect not a great seal.

Another hose suspect is the one from fuel housing to the VRO fuel inlet. The spring clamp is loose but also believe the O'Rings inside this barb in the housing are worn, all moving freely. Could this cause an air leak to make the system over oil? Even though the fuel separator is like a tank.

Like I said it's more prominent at idle than high revs. But may be impeding performance regardless....

I will try getting the gauge to work and going through the steps.

Damn OMC, hahaha.

 

[Riley C]

I will keep the search for the air leak culprit, I had air in the line 3 inch long in the clear hose while running. But until then I want to see what you guys think.

See the link below.

This is when I first got the boat. Maybe I'm just going insane, I swear that's more smoke than at 50:1 premix.

This was before the service. It seems to smoke more in the test tank.

https://www.dropbox.com/home/150 Ocean Runner?preview=IMG_2008.MOV

Maybe this is just what the 60degree loopers are like.

 

[Chris1956]

That motor should use no more than 2% oil (50::1). They actually run about 60::1. You report 3% oil usage, which is excessive. Excessive oil usage can be caused by an air leak in the gasoline supply line. Check the seals on the main strainer under the airbox. Air leaks are often located there. Other places are at the water separator. You do have one, right?

Other things: Fuel primer bulb should not go flat. That is a fuel restriction upsteam of the primer bulb. If the fuel tank vent is clear, suspect the antisiphon valve. Some of those have a filter on them, that can clog. I removed the A-S valve om my boat, as I had trouble with it.

If the fuel primer bulb goes flat, that indicates a fuel restriction. Your motor should have a "Check Engine" alarm, activated by a vacuum sensor on the gasoline supply line. It would seem like a check of this alarm is a good idea.

 

[Riley C]

That motor should use no more than 2% oil (50::1). They actually run about 60::1. You report 3% oil usage, which is excessive. Excessive oil usage can be caused by an air leak in the gasoline supply line. Check the seals on the main strainer under the airbox. Air leaks are often located there. Other places are at the water separator. You do have one, right?

Other things: Fuel primer bulb should not go flat. That is a fuel restriction upsteam of the primer bulb. If the fuel tank vent is clear, suspect the antisiphon valve. Some of those have a filter on them, that can clog. I removed the A-S valve om my boat, as I had trouble with it.

If the fuel primer bulb goes flat, that indicates a fuel restriction. Your motor should have a "Check Engine" alarm, activated by a vacuum sensor on the gasoline supply line. It would seem like a check of this alarm is a good idea.

Hi Chris,

Cheers! Yeah there is the old OMC old fuel water housing, I have not pulled it down other than change filter hoses, primer to it. The fuel strainer looks original to but no cracks, maybe replace this any way?

I don't believe I have a A-S Valve as I was able to syphon the whole tank out to the bucket on ground lower than the boat?

I have a long 3/8 vinyl hose I could bypass all the way to the filter strainer and start from there I guess.

The check engine definitely works, vacuum switch I did test per the manual.

I think it's a little bit of air getting in but maybe not enough to set alarm off.

 

[jakedaawg]

No reading on the vacuum guage is not necessarily an issue. The bubbles are.

hose clamps are not acceptable. I prefer Oetiker clamps. Many use cable ties.

just got to find the leaks...

 

[Riley C]

No reading on the vacuum guage is not necessarily an issue. The bubbles are.

hose clamps are not acceptable. I prefer Oetiker clamps. Many use cable ties.

just got to find the leaks...

Cheers Jake,

I redid all the fuel clamps with either zip ties or plastic clamps used on mercury fuel lines. The only metal hose clamps are at the tank, bulb and filter.

I did a test with have two primer bulbs. I primed both bulbs, then vice clamping before primer bulb after the filter housing. This Primer is rock hard after three hours.

The bulb before filter between thank tank is soft as.

Suspect shitting or something happening in the tank.

Almost there I think.

 

[jakedaawg]

After all the bubbles are gone and vacuum is not over the limit an oil consumption test should be performed. Depending on the results of that will dictate whether VRO replacement or bypass is necessary. Unfortunately, those V6's dont tend to do well with a VRO delete. You really need to use it as at least a fuel pump.

 

[Riley C]

After all the bubbles are gone and vacuum is not over the limit an oil consumption test should be performed. Depending on the results of that will dictate whether VRO replacement or bypass is necessary. Unfortunately, those V6's dont tend to do well with a VRO delete. You really need to use it as at least a fuel pump.

Thanks Jake,

I definitely want to keep the vro going. I premixed the last 140, got over it. Especially if it sat for a little while.

I’m happy if it’s half the smoke at idle put it that way.

Ill keep you posted.