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jwcrawford81
04-29-2013, 11:41 AM
Boat ran 25-30 mph when first in water then got slower and slower. When you open throtle to full position it has no power in gear. However, when in neutral it revs like expected. I think I can hear the fuel pump running constantly, is it supposed to do this? Could this be fuel problems or transmission problems? Boat has new plugs, new rotor button, and fuel pump is 3 yrs old. Need help or suggestions.

88 PS190
04-29-2013, 12:12 PM
With boat OFF and in neutral check prop shaft for free rotation

Check underwater gear for ropes, fouling.

I bet it doesn't turn well. Any transmission problem would be engine revs no forward motion, or boat won't go to neutral.

My bet is that the shaft is bound somehow, did you hit anything?

eurosysytem0
04-29-2013, 01:04 PM
Whats the boat? If its got the old style distributor with points and capacitor, it could be the capacitor.

jwcrawford81
04-29-2013, 04:07 PM
Checked prop shaft and it turns freely. Ran boat yesterday out of water in gear and ran fine without load. Problem seems only to be when boat is in water.

jwcrawford81
04-29-2013, 04:08 PM
1997 Prostar 205.....not sure what style distributor.

jmhjgh
04-29-2013, 04:12 PM
Make sure the gas valve is turned all the way on (located on top of the gas tank behind the rear seat).

jwcrawford81
04-29-2013, 08:23 PM
checked gas valve its open. took off fuel line at pump and drained as much gas as i could going to check fuel pump tomm and put fresh gas in

j.mccreight@hotmail.com
04-29-2013, 08:56 PM
I have heard that the anti-siphon valve can get clogged and cause loss of power, try loosening the fuel cap so the tank does not go into a vacuum and see if the problem is still there...

jwcrawford81
04-30-2013, 10:29 AM
do you know where the anti syhon valve is

jwcrawford81
04-30-2013, 04:43 PM
Talked to the boat center that tried to fix my boat. They said they checked fuel lines fuel pump and fuel filter everything was good. Not sure what to check next. Any advise?

jwcrawford81
05-01-2013, 03:29 PM
Took boat to lake today after draining gas and filling with fresh. Still performing same way.....see video.

bsloop
05-01-2013, 03:53 PM
I had debris in my anti siphon too. It is a 1.5" fitting at the fuel tank. I would not trust the shop saying they "fully" checked the fuel system.

I installed a permanent fuel gauge in-line just before the carb. This lets me see that I have fuel pressure and can help trouble shoot anything down line if needed.
The reason I suspect fuel delivery somewhere is power and rpm loss is only occurring under load. Unloaded, the demand is not as great and a partial blockage may be able to deliver enough fuel to not cause a problem.

jwcrawford81
05-01-2013, 04:54 PM
Took the boat back to the lake. Now it only revs in neutral to a certain point then acts the same as in drive. Put new gas in with sea foam. I will try to post a video. The fuel pump seems louder than normal. Is it possible the fuel pump is working until it has to pump a lot of fuel at once?

jwcrawford81
05-01-2013, 05:22 PM
Thanks bsloop I will see if I can find it tomorrow. I looked yesterday and only saw two lines one had a shut off valve and the other didnt. Does it have a line attached to it?

mikeg205
05-01-2013, 06:06 PM
Fuel pump supplies constant pressure - - do you have the correct pressure on fuel line to TBI - looks like fuel is not making it to TBI consistently....IMO - have you also checked the fuel pump intake screen?

thatsmrmastercraft
05-01-2013, 06:09 PM
............

mikeg205
05-01-2013, 06:12 PM
Looked at movie again...is that the fuel pump howling like that? On my TBI when I give it gas the flow of fuel increase...your seems to be dropping out and then the you run lean when the throttle body opens up... I am betting on a bad fuel pump - Napa carries them online... or the screen at the bottom of pump is fouled... CC2MC I believe just had the same problem. I cleaned mine out in 2011 - I was surprised I got any performance at all.

Dylan
05-01-2013, 06:13 PM
Fuel pump supplies constant pressure - - do you have the correct pressure on fuel line to TBI - looks like fuel is not making it to TBI consistently....IMO - have you also checked the fuel pump intake screen?

After watching the video, I agree. Check fuel pressure. Can you pull codes from the ECU?

mikeg205
05-01-2013, 06:13 PM
I had debris in my anti siphon too. It is a 1.5" fitting at the fuel tank. I would not trust the shop saying they "fully" checked the fuel system.

I installed a permanent fuel gauge in-line just before the carb. This lets me see that I have fuel pressure and can help trouble shoot anything down line if needed.
The reason I suspect fuel delivery somewhere is power and rpm loss is only occurring under load. Unloaded, the demand is not as great and a partial blockage may be able to deliver enough fuel to not cause a problem.

Bsloop - where did you get that guage? that's a pretty neat idea...

bsloop
05-01-2013, 06:23 PM
The anti siphon valve is usually screwed onto the right angle fitting as it comes out of the gas tank headed forward toward the engine. It will usually be threaded on one end and barbed on the other to accept the fuel line. The fuel shut off valve sounds "aftermarket" and is probably not necessary, possibly a cause of the problem depending on the valve???

Google image - "anti siphon valve fuel tank" Many images of the valve and location will come up.
This is another trouble shooting suggestion - http://www.justanswer.com/boat/6z9vs-1999-merc-cruiser-454-cubic-inch-boat-performs.html

The pump changing sounds definitely sounds like an increasing restriction. Could be a hose getting soft and collapsing too. Our fuel lines are pre-ethanol so this may be taking its toll as well. As the link suggests a vacuum gauge may be your trouble shooting friend as well.

My anti-siphon restriction got progressively worse over the course of a season. When it started, I could run for 10min+ or longer then start losing power, then less time and less power. I threw carb rebuild (found a cracked float anyway), fuel pump etc at it til I finally got a vacuum gauge.
http://www.harborfreight.com/fuel-pump-and-vacuum-tester-93547.html

http://proboat.com/attention-to-detail/170-the-vacuum-gauge-tool.html

André
05-01-2013, 11:06 PM
... have you also checked the fuel pump intake screen?

Do this.
If you don>t know how,do a search here.

mikeg205
05-01-2013, 11:10 PM
http://www.rockauto.com/catalog/raframecatalog.php?catalog=26&partnum=P60987&a=FR26-P60987-88113

fuel pump cheap... to have

JimN
05-01-2013, 11:31 PM
Took the boat back to the lake. Now it only revs in neutral to a certain point then acts the same as in drive. Put new gas in with sea foam. I will try to post a video. The fuel pump seems louder than normal. Is it possible the fuel pump is working until it has to pump a lot of fuel at once?

This style of pump doesn't like running out of gas but it's not as sensitive as the in-tank pumps. If you have a primer bulb, connect it at the tank and use it to augment the fuel flow- if it helps, check out the fuel line from the tank to the pump. If you want to be proactive, just replace that section of hose with something that's OK with ethanol. If it works, you know you found it. If not, you know that you're good fro another 20 years.

jwcrawford81
05-01-2013, 11:57 PM
Yes mike the fuel pump is louder than I remember. Do I need to take off the fuel pump to get to the screen? I will also look for anti syphon valve again. Thanks for the advise!

02ProstarSammyD
05-02-2013, 10:47 AM
Mine did the same thing last year. In the driveway you aren't under load. When I put the boat under load it wouldn't go above 25. Turned out to be a bad connection at the fuel pump but any fuel pump issues can show the same. Test your pressure under load first and foremost

mikeg205
05-02-2013, 10:50 AM
Yes mike the fuel pump is louder than I remember. Do I need to take off the fuel pump to get to the screen? I will also look for anti syphon valve again. Thanks for the advise!

Yes, you need to remove... Use a good box wrench... when you replace the pump do not over torque the line connections.

Took me about an hour - start to finish... it should not be howling like that.

jwcrawford81
05-04-2013, 06:31 PM
Cleaned screen on bottom of fuel pump. Ran it today in driveway then took to the lake. Ran like a new one! Fuel pump no longer makes so much noise. Thanks for all the help!! Glad I didn't have to take it back to the shop!

mikeg205
05-04-2013, 06:35 PM
I would buy that pump from rockauto- yours was squealing pretty good... for 84 bucks plus shipping - it would be cheap insurance - imo...

congrats on the cheap fix...those are always best...

JimN
05-04-2013, 07:17 PM
uas an FYI- fittings on fuel, brake and other fluid-carrying lines need what's called a 'flare-nut' wrench. It's like a box wrench with enough removed to allow the line to pass through- it adds support for the nut and if it flares a bit, it won't slip off and round off the corners.