91 200 HP Fuel Starvation

[fab19992000]

Yesterday I ran 70 miles offshore for tuna on twin 200's (90 200 2-stroke ETXD, 370 hours). Everything was running great until one engine started to drop RPM's (up and down, up and down 2000-4100 rmps). At that point, I stopped that engine and started *****ing backing with the other. After about 1 1/2 hours I started up the bad engine and ran another 30 miles when it started to happen again. We found if we pump the primer bulb the rpms would stay up. I'd even shut the engine off for about 15 minutes and pump the bulb and could run for another 20 minutes before it dropped RMS again. Finally we had to continously pump the bulb to get back in.

I'm reading about o-rings on the engine filter and fuel pumps. And I'm willing to replace all to have the extra insurance. I've also check hoses, and the checked out good. The Fuel/Water seperators are new.

Any advice will be greatly appreciated.

Thanks,

Frank

[fab19992000]

forum posts

based on what I'm reading on the forum, it sounds like my problem(s) might be fuel line, fuel filter gasket, and/or the fuel pumps. I'll replace the gasket and pumps, and will double check the lines.

Good info on here, I hope it works.

If you have other suggestions, please let me know.

thanks,

fb

[Tucker]

My money's on the fuel pumps. If air was entering before the priming bulb you probably couldn't pump it up. Take the pumps off and if there is gas behind a pump the diaphram is bad. They sell replacement diaphrams but a new pump is <$40. Don't forget to get a gasket.

[fab19992000]

thanks

Thanks Tucker,

Do you know if the FUEL PUMP ASY comes with the Gasket? I just order two of them.

Thanks again,

Frank

[Tucker]

Sorry for the late reply, negative the gaskets are separate. Woh, only 370 hrs! The boat's hardly used! I got a 20' Grady Escape with a 150 OX66. Wish I had a 200. It suppose to be a much better performer. This is a great website and you should do a search of your engine and read every post. There are a handfull of real sharp guys on here that tell the "rest of the story". They've bailed my ass out several times.

[fab19992000]

thanks tucker

Hey tucker,

thanks for the heads up on the gaskets. I have a local dealer here in the Portland area that actually has them in stock. The Fuel pumps are on the the way. Hopefully, I'll be out and running by this weekend.

PM me if you want an update. I plan to do a bunch more tuna fishing off the oregon coast.

Yes, I feel pretty luck with twin 200 two strokes and a 25 ft grady sailfish. When it's running is much better than the Striper and trophy I've owned.

Thanks again,

frank

[fab19992000]

It happened again

Ran two days, first day there were no problems. Second day on the way back in, I started to lose RPMs again. Each day we ran over 50 miles off shore.

Fuel pumps replaced, Fuel lines Replaced, and Fuel filter on engine replaced.

Anybody have any idea of what to do next?

thanks,

frank

[99yam40]

Is it the same motor as last time?
Does it help to pump bulb?
Are both motors fed from same tank or different tanks?
If different tanks I would look at fuel or fuel tank parts. pick up tube ,screen, check valve, connections,etc

[fab19992000]

same engine
yes it helps to pump the primer bulb
yes, both motors are fed by the same tank (both tanks had fresh gas, only used the one tank yesterday.

I'm not exactly sure how the fuel lines are connected. I have two fuel/water seps the feed two two tank switches. I keep both switches set to the same tank. I plan on putting new seps in this week.

One added variable, I have a flowscan meter hook to both engines, there's a swich to change the meter from engine to engine. Both pickups are working intermittently. And the one, doesn't work most of the time. I plan on taking the whole system out.

Thanks for the response, appreciate all the posts and people like you trying to help me out.

Frank

[99yam40]

look at this post and see if it will give you a way to test your fuel system

HOW TO: Testing your boats fuel system. - iboats Boating Forums

[fab19992000]

Thanks for the info. This looks like pretty indepth article.

fb

[Tucker]

Ok, Frank what was the problem?? A whole lot was said here and anxious souls need relief. That's how we learn; from others problems. Sorry you have to be a donor.

[brody]

my dad had a boat once that would die out suddenly when ran at high rpms for extended time and had same problems you are discribing. Turned out the fuel vent was pluged on the tank creating a vacume and the fuel pump was unable to pull fuel. Just throwing that out there, may be worth checking good luck. Brody