# Perplexed with fuel problem



## lemaymiami (Feb 9, 2007)

Could be almost anything - and possibly not related to the things you're already done... Here's the first thing a pro will do if you brought your rig to him (or her...)... They'd get a known good portable fuel tank that came with a known good fuel line and good fresh gas - hook it up to your motor and see if the same problems occurred.. This is done to eliminate, if possible the fuel system in your skiff as the problem. If, on the other hand, that new fuel source fixes your troubles... Then it's not your motor at all... PS... bad fuel economy and a bit of an oil slick when idling describes every carbureted two stroke - it's how they run...

Don't ask me where to go from there since I'm not a tech -just a guy who runs and runs, and runs... whatever boat I'm working out of... On Monday I had a 300 hour service done on my E-Tec 90 and noted that I was having a problem with the motor losing a cylinder momentarily once or twice a day...(three cylinder motor... like your ninety - but no carburetor at all, completely fuel injected, computer controlled... ). They found a bad injector, replaced it under warranty and said I was good to go... Yesterday running out of Chokoloskee - you guessed it... my troubles came back as though nothing was fixed at all... In fact I came the last three miles with customers aboard barely able to get up on plane.... This morning when the dealer opens I'll be sitting t their door - and won't be fishing anyone until it's sorted out... Lucky me...


----------



## HewesYourDaddy (11 mo ago)

@lemaymiami Thanks for the quick response. I have a portable tank in my driveway ready to rip. The problem is that its been raining with lightning every evening this week in New Orleans. I was originally hoping to have this sorted out so I could make a tournament this weekend. Now I'm not so sure. Since we will have bad weather today, I'm going to break down the carbs and see if I can fix the problem that way. I'm basically throwing fixes at it until I can test it. The only certainty at the moment is that my motor started first crank before the fuel pump install. It wont start after the install. 

A friend who would know told me that I likely shook some dirt loose in the carb when I ran it out of gas, to start my problem. The addition of the new fuel pump was probably enough pressure to lodge the dirt into the jets on the carb.

Seems very possible to me. I haven't gone through the carbs since I've owned the boat. I figured today is the day. I will report back with results.


----------



## RABillstein (Jan 10, 2019)

I used to have the same engine, same problem. I fixed mine by replacing the primer bulb. It was allowing fuel to drain backwards through the fuel line. Yamaha 90 2-stroke bogging


----------



## mwolaver (Feb 6, 2014)

Yes, run on the tank. The ONLY issue I ever had with the powerhead section of my 90/2 was carb related. Those jets are really small, one idle and one main.


----------



## Mike Haydon (Dec 19, 2019)

I would suggest running it on the portable before cracking the carbs. Sinking them can be a pain, especially if it wasnt needed. The more you tinker with 2 strokes the more you will have too in my opinion. I'm with the other poster and thinking bad primer bulb. If it cracked or something it will lose pressure.


----------



## coconutgroves (Sep 23, 2013)

In my experience, that behavior is always the low pressure fuel pump. You've replaced it, but haven't been able to run it yet. Get that sucker cranked up on a flush muff, then go run it. It sounds like you are not getting fuel to the engine now after replacing the pump.

Bogging down at wide open throttle is a fuel demand issue. I've had my carbs redone and still had the same issue to learn it was the fuel pump.

I don't buy the dirt in the carbs. You ran it with seafoam, and the fuel pump has a filter.

Did you replace the entire low pressure fuel pump, including the gasket?

Check you are getting fuel through your line. Take off the fuel connector to the engine and pump the bulb in to a gas can. Make sure this is flowing.

Check the fuel connector to the engine. If those are faulty, they can restrict fuel flow.

Make sure the bulb is installed close to the engine and is vertical with the arrow to the sky (not laying sideways, or line turned over pointing down to the floor).

I have a 1995 115 and every time this issue happened, it is either the pump, or the bulb.


----------



## Travisloyd07 (Jan 31, 2014)

I had a similar issue. Ended up being a small crack in the FWS housing.


----------



## lemaymiami (Feb 9, 2007)

A quick end to the story on my E-Tec 90... All it was... was a brand new spark plug - that was bad and failed during that first day on the water... Boy did I get lucky (and as a side note, running outboards since 1974... and never had a spark plug do this in all those years, including the last 26 years in hard commercial service....).


----------



## Frank Ucci (Jan 20, 2019)

Good deal Captain LeMay! Years ago I had a brand new Suzuki 115 that would not run smoothly. Had it back to the shop numerous times in the first 6 weeks but the problem couldn't be solved. Just as I was about ready to throw the engine through the shop window, the mechanic changed the NGK plugs. The engine ran flawlessly for 12 more years. Last year, my 2004 Yamaha 300 HPDI developed a miss at cruise rpm. Fuel checked good, coils checked good and I sent the injectors out for cleaning. Engine still missed at cruise. Checked the NGK plugs (with less than 50 hours on them) and found one of the plugs with a suspect hairline crack near the spark tip. I switched out the plugs and the engine now runs great. Plugs are cheap and easy to change. It might be a good place to start when your engine is acting up.


----------



## lemaymiami (Feb 9, 2007)

When I picked up my skiff yesterday (the second time this week....) I talked to the service manager (Oscar at SeaPower, now a Yamaha dealer but still a very skilled outfit for E-Tecs...) about picking up a plug or two (a set for me is only three plugs...) to keep for these kinds of events and he actually said he doubted I'd ever need them and that this kind of problem is very rare with brand new plugs (last Monday they did a 300 hour service and new plugs are just part of the routine... ). After we talked I decided against that extra set of plugs. If it was a mistake on my part - I'll be the first one to know about it... I can usually put 100 hours on a motor in April alone so my gear doesn't just sit... I won't mention the miles and miles on the road clocking about 194 miles each day commuting down to Flamingo or Chokoloskee... This is E-Tec number four for me so I'm pretty used to the potential problems you can run into with them. Wish they were still being made -not looking forward to the change out to a four stroke when it has to happen (hopefully the motor scene will settle down enough in a year so that prices (and deals if any) stabilize. I'm hearing more than a few accounts of dealerships (for every brand motor...) struggling since they can't get the motors customers are wanting. Can you imagine how it hurts their bottom line when they're turning down potential customers that want dual or triple motor setups on bigger boats -and every one of those motors a high ticket big block item?

Just can't wait until November.... the folks running our country need a reality check.


----------



## JC Designs (Apr 5, 2020)

My guess is she is sucking air at the quick connect. Again, just an educated guess as it is next to impossible to do diagnostics w/out the engine in front of me. Next suspect would be the primer bulb. Known good tank, vacuum gauge with T fitting, 12” clear hose and two barbs are your friends.


----------



## HewesYourDaddy (11 mo ago)

Thanks to everyone who responded. After changing the fuel pump, I could not get the engine to start. I was planning to clean the carbs and figured I should replace the spark plugs as it had been over a year since they were replaced. I went to crank it and the motor started right up. I took it to the launch to test it and the motor ran perfectly. I was able to make the sheepy tournament and use my boat. (This was the time crunch I was under). The problem seems to be fixed as I used the boat all last weekend too without any issues. I have noticed since then that my mpg has gotten slightly better and the engine doesn't cut out at idle like it used to. I still plan on rebuilding the carbs since I already bought the kits, but for now, the engine is up and running great.
In Summary:
Problem started> checked filters and bulb (Good)> Ran two bottles of seafoam and 20 gal of fuel through the boat (No Change)> Replaced fuel pump >Motor would no longer start> Replace Spark Plugs> engine starts and runs better than before the problem developed. Thanks again!


----------



## Smackdaddy53 (Dec 31, 2012)

They need that ignition!


----------

