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Catalina/Capri 25/250 Sailor's Forums

Catalina 250 Specific Forum

outboard motor

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mjnee
1st Mate

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USA
36 Posts

Initially Posted - 09/02/2009 : 05:41:06

I have a Yamaha 9.9hp 4 stroke. It is a 2003 and very little used. My problem is starting. It has an electric start and although it turns over it will not start unless I cover the air intake with my hand once while cranking then try crankingj again. Even then it will run for awhile then stall. I have replaced the in-line filter, replaced the gas and added a stabilizer to address the alcohol content in the gas, added a carburetor cleaner to gas and tried a carburetor spray cleaner. I have also replaced the priming bulb on the gas tank line. I did this because after squeezing the bulb it dose not stay hard

I'm guessing its a problem in the fuel line but I cannot figure out where the problem is. Any ideas

Inis Ni'

Edited by - on

John Russell
Master Marine Consultant

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USA
3444 Posts

Response Posted - 09/02/2009 : 06:43:08

Since it starts when you cover the air intake, I'd suspect that the choke isn't working correctly. May be gummed up. I'd give the choke mechanism a good cleaning. Put in new spark plugs just to be sure.

Edited by - on

Sloop Smitten
Master Marine Consultant

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USA
1181 Posts

Response Posted - 09/02/2009 : 07:38:59

As John stated, it sounds like something related to the choke. I found this article talking about someone with a similar issue. He had problems with his idle jets which didn't come into play until the choke started disengaging. You should be able to verify whether the butterfly valve in the carburetor throat is closed when you try to start the engine cold. That's basically all the choke does and you are duplicating that by holding your fingers across the carburetor float.

[url="http://www.marineengine.com/discus/messages/12481/283937.shtml"]Yamaha 9.9hp 4-stroke starting/running problem [/url]

Edited by - on

Steve Milby
Past Commodore

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USA
5904 Posts

Response Posted - 09/02/2009 : 08:00:43

The fact that the priming bulb doesn't stay hard suggests that the fuel might not be getting to the engine. Before you start tinkering with the engine itself, I think you should eliminate any possibility that the problem is in the fuel supply line. I used to have that problem occasionally, and suggest that, in addition to replacing the bulb, you replace the fuel line. Any tiny air leak can cause the line to lose it's prime, allowing the fuel to run back down into the tank. Depending on what it's made of, the hose can crack from UV exposure, resulting in a leak that you can't really see. Also, I'd replace the crimped clamp fittings on the new fuel line with stainless steel screw-type hose clamps. I have had fuel leaks at those connections, and, if gas can get out, air can get in. If you have eliminated all possibility of problems with the fuel line, and the engine still won't start easily, then it's time to look at the engine itself.

Edited by - on

John Russell
Master Marine Consultant

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USA
3444 Posts

Response Posted - 09/02/2009 : 08:35:32

I forgot, check the air valve on your fuel tank. It needs to be open to avoid a vacuum in the tank inhibiting fuel flow.

Edited by - on

essen48183
Navigator

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USA
143 Posts

Response Posted - 09/02/2009 : 19:10:12

I had a similar incident that was solved by removing the carburetor and cleaning the jets with a single strand of "stranded" wire. The motor wouldn't idle because the idle jet was clogged, it would run covering the intake sometimes, and it would run if I throttled up. Wouldn't idle. Pain in the butt, but a free fix.

Edited by - on

mjnee
1st Mate

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USA
36 Posts

Response Posted - 09/03/2009 : 09:55:50

Once again, great advice. I think I'll start with the fuel line before attacking the engine. Does anyone know where I can get a schematic for the engine/carburetor? The manual does not have a detailed description and I'd rather not go in blind.

Edited by - on

Bob Jack
1st Mate

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USA
58 Posts

Response Posted - 09/20/2009 : 15:01:43

Wow...dejavu....same thing happened to me.Get ready for a long sad story.
Sorry for the late responce but I've been to busy to read the forum....busy... dealing with AN OUTBOARD MOTOR THAT WOULD NOT RUN BELOW 1/4 THROTTLE....that was making me crazy.
Here's my story and the ultimate outcome..which is good.I know your motor is different, but my saga may help you.
2006 Tohatsu 9.8 4 stroke. Light usage...sits on a lift over the water for months.
Hard to start...won't idle. First I took off the carb (not as hard as it seems...especially after you get over the intimidation factor)and gave it "a good cleaning" ( I thought) Put the motor back together with slight level of improvement in performancee. Threw out my old gas can,bulb, and hoses. Got new gas..Installed an inline filter.All of this over a three month period. After a while I became very good at taking off the carb and did it no less than 5 times. I could ripp that thing off now in 5 minutes with my eyes closed...but still had the problem.I found a guy in a chat room that calls himself "Tohatsu Guru" and he told me that ,quite simply, I wasn't getting the carb clean. So...here's what I finnally did...and it worked.
Take off the carb...tear it down being careful to remember screw placement etc.....shoot carb cleaner (guru says it's not good enough...need dip...so I used extra) with that little staw into every opening and port.Take off the float pin...it's not hard.. I got a can of air and shot that the same way through every available opening...did this for TWO DAYS...and finaly...the coup de grass..I put the torn down carb and parts in an ultra sonic cleaner. I had done this before with out success. This time though, thanks to a guy at Marine Trading Post who has the same motor...I paid special attention to three tiny (so tiny you can barely see them) holes in a plate on the carb. They're clustered together forming a triangle..look hard or you'll miss them. I think they are for idleing and can get easily clogged.He suggested inserting a tiny wire, being careful not to break it off...that would be the end of the experiment.I did not do this, but i would if needed.
Anyway...after that..the motor started on the first crank and it's running great...and idling great too...like new.
I blame the ethynol in our fuel and have found a way to get only 100% gas in the future.
Hope this is useful.
Bob

Edited by - on

willy
Captain

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USA
422 Posts

Response Posted - 09/20/2009 : 18:07:36

Mike,
Your issue came up today as I was leaving the pier when one of the other guys was complaining in the parking lot that his Yamaha 9.9 DID NOT HAVE A CHOKE! I really found this hard to believe but the guy is a retired engineer so I am amazed that he would get it wrong. As I was late for dinner and didn't want to get in trouble with the admiral I didn't have a chance to actually check, (although I will tomorrow, but I have to ask...does your motor have a manual choke?
Willy

Edited by - on

essen48183
Navigator

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USA
143 Posts

Response Posted - 09/20/2009 : 19:14:15

It actually could be the case. The newer hondas don't have a choke, they have a fuel enrichment gizmo that defaults to "on" and is turned "off" by a heating element (that does burn out requiring replacement). If Yamaha has a similar one and it was malfunctioning... it'd be a likely part to replace after new fuel, new filter, new bulb, etc.

Regardless, a wise investment is the factory service manual for any outboard/car/truck... really helps in diagnosing and repairing. I like to order the shop manual while the engine is running fine, that way I have it when the inevitable problem arises.

Edited by - on

Sloop Smitten
Master Marine Consultant

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USA
1181 Posts

Response Posted - 09/21/2009 : 07:05:38

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Regardless, a wise investment is the factory service manual for any outboard/<hr height="1" noshade id="quote"></blockquote id="quote">
When I had my Honda 8Hp O/B I ordered the factory service manual and it was great. I did several repairs with it I would not otherwise have attempted so when I ordered my Tohatsu 9.9 I ordered the service manual as well. This manual is practically worthless. If you have a Tohatsu 9.9 don't bother spending the money on the manual. Not enough information in it to allow you to undertake a repair with any confidence. My 2 cents.

Edited by - on

moserd
Navigator

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USA
149 Posts

Response Posted - 09/21/2009 : 10:14:40

I am very surprised to read about your Tohatsu manual. I have the Mercury 8 HP 4 Stroke which is basically the same engine as the Tohatsu. I purchased the $50.00 manual from Mercury which I find to be quite informative.

Edited by - on

jbkayaker
Captain

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USA
299 Posts

Response Posted - 09/21/2009 : 10:31:16

That filter in the gas tank at the end of the fuel pickup MIGHT also include a small ball bearing check valve to prevent fuel from running back out of the pickup line. If the ball bearing gets stuck in the closed position the carb gets little or no fuel. I had that problem on my Sea Doo water scooter. But the difference is that it would not start at all.

Edited by - on

essen48183
Navigator

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USA
143 Posts

Response Posted - 09/21/2009 : 10:35:37

I too was disgusted with the tohatsu manual... worst i've ever seen.

Edited by - on

Ed Cassidy
Captain

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USA
365 Posts

Response Posted - 09/21/2009 : 11:00:26

My Yamaha 9.9 does not have a choke, it has an electrical enrichment valve. I had a stalling problem with mine after I cleaned the carb. Found out it was because the main jet in the carb must be positioned correctly if you remove it to clean.
Ed

Edited by - on

britinusa
Web Editor

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USA
5404 Posts

Response Posted - 09/22/2009 : 10:37:42

We got some water in the fuel line (100% humidity is all I can think of) and had a heck of a time clearing out the gunk that got all the way to the carb (Nissan 9.8hp 2009)

Did the carb strip down thing, flushed fuel through the line an out of the carb. WD40 in every crevis I could see, then more fuel flush.

Then several minutes of cranking and she ran as good as ever. It's been a while since my last sail/engine run, so I'll flash it up before we leave home for the party at the Columbia Regatta in Biscayne bay in a few weeks.

As mentioned in posts above, ethanol is the culprit! when I flushed the line out first time, a gooey tan colored liquid emulsion flowed till I got clean fuel. The gunk was in the carb too.

Now when I finish the engine flush I detach the fuel hose and bring it into the garage, same with the fuel tank.

Paul

Edited by - on

frog0911
Master Marine Consultant

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USA
1349 Posts

Response Posted - 09/22/2009 : 19:35:29

Paul, do you put sta-bill in your fuel as soon as you purchase it. I put it in when I purchase fuel and have never had any problems in my motors, boats or generators.

Edited by - on

Bob Jack
1st Mate

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USA
58 Posts

Response Posted - 09/25/2009 : 11:48:43

Jerry,
Do you disconnect the fuel line and let the engine run out of gas before leaving ?
Bob

Edited by - on

piseas
Former Treasurer

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USA
2017 Posts

Response Posted - 09/26/2009 : 19:59:24

Bob, my Honda dealer said it was not necessary to run engine till empty. I do however use the boat almost once a week. I do however, flush the engine after every use. I am in saltwater.
Steve A

Edited by - piseas on 09/26/2009 19:59:54

Bob Jack
1st Mate

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USA
58 Posts

Response Posted - 09/27/2009 : 15:31:40

Jerry,
I've heard both methods have their ups & downs. Your's might allow gas to go to varnish in the littlest jets...and mine might cause rubber parts to dry out....It's also a pain having to pump the gas up each time I start. Seems like it takes forever to start..then runs fine. Actually, I think I just overeacted to the Ethynol problems I expeirenced for so long.Now that I've replaced my gas tank, fuel lines,and pump bulb, and installed a second (in line) fuel filter and ONLY use 100% gas, purchesed at a marina....and use Sta-Bill, I think maybeI can return to normal.
Thanks
Bob, Naples Fl

Edited by - on

Bob Jack
1st Mate

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USA
58 Posts

Response Posted - 09/27/2009 : 15:36:00

Steve,
Oop's.. sorry for getting your name wrong in my geeting.. I'll pay more attention in the future,
Best Regards,
Bob

Edited by - on

piseas
Former Treasurer

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USA
2017 Posts

Response Posted - 09/28/2009 : 13:19:05

Bob, No problem. I have been called a lot of different names! At least yours was a clean one.

Steve A

Edited by - on

superbob
Navigator

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USA
200 Posts

Response Posted - 10/03/2009 : 09:53:16

I have a '99 9.9 Yamaha/electric starter mounted on my 250. Had a similar problem. Replaced the fuel line which solved the problem. BTW: It's been never necessary to cold start the engine by using the choke. Couple of cranks and we're good to go.

Edited by - on

Dave Bristle
Master Marine Consultant

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Djibouti
10005 Posts

Response Posted - 10/03/2009 : 11:08:51

Regarding the run-dry debate, I think Honda is telling its dealers and mechanics that it's better to:
1. Treat every tank of gas with stabilizer.
2. Not run the engine dry, so that stabilized fuel remains in the carb.

Apparently their experience is that running dry causes the residual fuel to evaporate and create varnish, particularly in the jets.

I followed that advice, increasing the stabilizer content the past two winters with my little Honda 2 dinghy kicker--the next spring it started on the 2nd pull (with fresh gas in the tank).

Edited by - Dave Bristle on 10/03/2009 11:39:09

Bob Jack
1st Mate

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USA
58 Posts

Response Posted - 10/04/2009 : 07:48:03

Dave,
After much time and involentary experimentation, I have come to the conclusion that you and Honda are correct.
I had massive ethynol problems going back 5/6 months...removed and cleaned the carb 5/6 times...with varying degrees of success.After each repair, when it was running o.k...I'd dutifully disconnect the fuel supply and let r' run dry. (which is a pain for two reasons...takes longer to shut down and longer to pump up the fuel and restart). My problems always returned...sometimes overnight.
Finally, after replacing every single component in the fuel chain, using 100% gas and Stabil...and ultra cleaning the carb...she started and ran good.I decided to try your method. I think my problems are over.
Has been running like a top for days now. This morning she started cold...with one pull....didn't even need the electric starter !

Edited by - on

Voyager
Master Marine Consultant

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USA
5389 Posts

Response Posted - 10/04/2009 : 20:00:31

The first winter I had the Honda 8, if opened the carb and found bits of black stuff inside the bowl. I replaced the gas filter and the fuel-water separator and did not have any more trouble with the black stuff.
Last winter, I got the carb rebuild kit from Honda and cleaned it according to the maintenance manual, and the engine has been running fine all summer.

I also use stabilizer (blue) and cleaner (pink) in every tank

Runs great now, but used to stall at low idle

Edited by - on

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