1993 150 Evinrude Intruder Fuel Restriction alarm and overheats at idle under load

[runninfarmer]

Hi All,

I've been struggling with a constant fuel restriction alarm at around near to WOT on a 1993 Evinrude 150 intruder (E150GLETG). Starts and idles great (albeit an occasional miss), but also occasionally overheats if idling too low under load. Without a load it never overheats at any RPM. I believe the vacuum alarm to be true, but I haven't tested the vacuum yet. I've done a lot to this motor, including:

1. Changed out OMS pump for two conventional fuel pumps (in series) with a conversion bracket. I now run 100:1 Amsoil outboard premix. Pulse limiter changed out with full flow nipple.

2. Completely rebuilt all 6 carbs, used a sonicator for cleaning with Simple green. Used Systematched parts.

3. Brand new o-rings on fuel distribution rails.

4. Decarbed with Power Tune

5. New QL16V spark plugs

6. New water pump assembly

7. New fuel primer bulb and hose

8. New fuel fill hose and new 3/8" fuel supply hose.

9. New inline K&N filter (glass housing)

10. Anti-syphon valve removed from tank.

Diagnostics I have performed, are running with fill cap off to test vent, and appears to be venting fine as alarm still goes off with fill cap off. Bulb also doesn't appear to collapse. I have noticed a small leak at the VST fuel supply inlet at the filter (new gasket on the way) and I've also ordered VST bowl gasket and primer solenoid seal kit. Could leaks at these locations cause a fuel restriction issue?

Should I eliminate the K&N filter and let the VST filter do all the work? Maybe too much pressure drop with the inline filter? I have blown air through tank diptube and I can hear it bubbling, but I haven't pulled it yet, saving that for very end if I absolutely have to as its hard to reach.

Thanks for the help!

 

[James R]

The symptoms indicate that the motor is running lean. My own experience, not that it is a lot, is that these types of motors don't run well on the double stacked fuel pump system. Had to use the OMS pump. Also ran these motors on 50:1 mix with the oil side disconnected.
Used the double pumps on the 90* motors with excellent results but the model type you have gave me a problem. Hope this helps.

 

[runninfarmer]

So I determined it's definitely leaking at the filter, but how far does it go on? It appears when I installed the cap back on it distorted the gasket. Is there a trick to keeping the gasket from getting wonky, lol? It's not explicitly spelled out in my service manual.

I'm surprised you had better luck with the OMS pump, wouldn't the pulse limiter make it weaker than the stacked pumps with full pulse flow? I use to have a 115 HP intruder that I put a single conventional pump on and also had excellent results. Never had a fuel restriction alarm.

 

[jakedaawg]

you need to run that at 50:1.

 

[jakedaawg]

As far as overheat goes, have you replaced impeller? That would be step one.

Its gonna run hotter at 100:1.

The vst cover can warp. I lightly tighten the screws making sure the are in the original threads.

I also have never had luck converting to 2 pulse pumps. We used electric on the race boats. I replace customer pumps with oem only.

Verify fuel restriction by teeing in a vacuum guage just after cowl connection just ahead of vacuum sensor..

What color is the vacuum switch? Grey or black? 2 different values depending on color.

 

[runninfarmer]

The Amsoil outboard product I run is a designed for running at 100:1 in outboards specifically, it's great stuff. Never have had a problem with it. I've actually read it was verified at 200:1 but definitely won't try that, lol. Cuts down on smoke and carbon, here's a link:

https://www.amsoil.com/p/outboard-10...EaAtw9EALw_wcB

Water pump is brand new. I will try my vacuum gauge next time out. The vacuum switch is gray. Do you have a link for a good electric pump? Also does it fit on the VRO bracket, or does it sit in the boat? I may go that route.

 

[oldboat1]

Don't go by the oil mfg rating, go by the motor rating (50:1). Post compression numbers (all plugs removed, crank until needle stops.)

 

[runninfarmer]

Have you not researched this oil? It’s not your typical TCW3. The Amsoil product has a heavy dose of additives and it’s full synthetic. In fact, I think performance would go down slightly at 50:1 with it. Compression is great, 85 psi average on left bank and 95 average on right bank. I’ve heard the early 90’s models were lower compression.

 

[oldboat1]

Sounds like your motor should be running perfect!

 

[runninfarmer]

Should be but it’s not, lol. Not on here to cause trouble but when a heavily respected manufacturer puts a guarantee on their product and have the data and testimonials I stand by it. Based on your response it looked liked you never clicked on the link I posted. Direct from their website:

“For pre-mix use in two-stroke outboard motors, personal watercraft and jet boats that specify TC-W3. For maximum performance, mix with gasoline at 100:1 regardless of the mix ratio specified for the equipment. Richer mix ratios may be used where desired.”

I ran this oil 100:1 in a 115 HP intruder for a whole season, never once overheated or had a fuel restriction.

I do appreciate the info on the stacked pumps and I will look into possibly going back to the OEM OMS pump. I just don’t like the idea of having an open oil side that could be an additional spot for an air leak, granted it shouldn’t if plugged right.

 

[oldboat1]

"Richer mix ratios may be used where desired.”

Seems that may be desired (i.e., tried?) Good luck with it. Post compression numbers.

 

[flyingscott]

Eliminate the K&N and run it without it. The 100-1 is fine with Amsoil pre-mix. Those motors generally run better with OMS pumps. Plug the oil side of the pump and you will have no air leaks. The V4 motors do not have fuel restriction alarms. If it is the VST gasket that is distorted you are torqueing it to tight. Remember it takes 2 standard pumps to equal 1 OMS pump.

 

[racerone]

Considering the cost of motors I would never run with 100:1-----Bearings need oil in a certain quantity in order to " work properly "----But every one has a different understanding of what happens to oil once fuel goes through the carburetor !

 

[flyingscott]

The Amsoil 100-1 pre-mix is a good product I.myself have run it for yrs with no.issues. They also back there product with an.excellent.warranty. I understand very well how a 2 strk is lubricated.

 

[runninfarmer]

Just to check, for those that had bad luck with the stacked pumps, did you change out the pulse limiter for a full flow NPT nipple? I could see how the limited pulse flow would not provide enough driving force for these pumps.

I'm going a bit against the grain but I'm going to bypass the VST with my stacked pumps and also block off the vapor pump pulse port in the block and I will retain the inline K&N filter. I know the small air leak I had at the filter contributed, but just seems like my pumps are emptying the VST tank too fast due to either outrunning the vapor pump or an altogether bad vapor pump. I tore it apart and it looked good though. My plan is to tee into the suction side of the pumps and still use the existing vacuum switch for precaution. This setup shouldn't be much different then a 90 degree V6, aside from the stacked pumps taking the place of the VRO2:

 

[runninfarmer]

Sorry for extra post, learning curve on posting pics, haha.

 

[runninfarmer]

**Update**

After bypassing VST, found it was ridiculously hard to prime the system. Decided to bite the bullet and tear floor up to get at pickup-tube. When I pulled it out, I tried to blow through it but it was extremely difficult. I saw it still had the screen but the screen wasn't that dirty. Is it normal for that much pressure drop across a pickup screen? Regardless, I tore that out and decided to reconfigure back to the VST. Luckily I had a spare vapor pump and filter with good gaskets to use. After making those changes it is now WAY easier to prime. I'm going to try to run it this weekend to see if I notice a difference. I will say having the VST makes it so much easier to prime, since it allows air to purge without needing to pull off hose.