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Author Topic:   Yamaha 85-HP Starving for Gas

woodyh2006 posted 05-12-2009 07:15 AM ET (US)
I have a RAGE 15 which has been converted to outboard drive from jet (with much help from continuousWave). It is a sweet little boat and suits the needs of my wife and myself, being trailerable to various campgrounds in our area. I have a 1994 Yamaha 85-HP motor which runs great at wide-open throttle and neutral idle, but has a problem with intermediate engine speeds with a load on the engine. I have had carb kits replaced, fuel pump replaced, spark plugs replaced, electronics checked, and I still have the same problem. I am living with this situation but another major problem is the motor runs smoothly when on plane turning anywhere from 3,500 to 5,500-RPM for about 15 minutes, and then shuts down to an idle, sucking the primer bulb flat. Thinking that it was picking up trash from a dirty built in fuel tank, I connected a new six-gallon tank with new line and primer bulb to the fuel-water separator, and got the same 15 minute run and then shut down. I have made sure the tank vents are open. I installed a brass tee in line prior to the fuel water separator with two ball valves so that I can run on either the built in-tank or the remote tank. By opening both valves thereby accessing both tanks it seems to run ok.This indicates to me that I have a vent problem. Are these two problems related?
jimh posted 05-12-2009 09:05 AM ET (US)
If the primer bulb goes flat, there is an obstruction upstream. Is the fuel-water filter upstream of the primer bulb? It sounds like the culprit.
woodyh2006 posted 05-12-2009 10:04 AM ET (US)
Thanks for the reply . No , the fuel water filter is downstream of primer bulb on both tanks . I have checked and cleaned this filter as well as the screen filter on the engine . Both were clean .
boatn posted 05-14-2009 05:21 PM ET (US)
if there is not an obstruction in the tank I'd check the fuel line. Sometimes they age and the inside of the hose breaks down.
woodyh2006 posted 05-16-2009 02:48 PM ET (US)
Hey thanks Boatn ,I just bought a new "premium " primer bulb and connecting fitting to the motor .I'll install these and replace the cheapy walmart bulb and connector. The fuel line is fairly new but I'll replace that as well .I try to burn midrange , no ethanol fuel but I don't have a source any more . I'll do a test run soon and let you know the result.
wezie posted 05-17-2009 10:23 AM ET (US)
There is most likely a screen on the end of the pick up tube, inside the tank. Do not forget to check that. It is small, but can be clogged.
Good Luck
towboater posted 05-17-2009 01:02 PM ET (US)
As long as you are replacing the bulb, blow lots of air back thru the fuel lines into both tanks. This will guarantee both lines and the pickups are clear and the tanks are venting properly.
If your vents are blocked, be ready to capture fuel coming back at you with a gas after you quit pumping air into the tank. If the gas doesnt come back at you, your tank is venting.
Its a long shot, some of todays water separators are so efficient, fuel additives actually clog them up yet they look really good when you pull them off to inspect.
Conjecture;
The filter is clear enough to cover idle speed and WOT has enough pump pressure to by-pass? Yeah, I know, seems nuts. Just saying, replacing the filter will eliminate the issue.
mk
woodyh2006 posted 05-18-2009 08:19 AM ET (US)
I appreciate everyone's input. It has been very frustrating to take the boat out and encounter the same problem and have the outing turn sour . Towboater , I think that you hopefully hit the nail on the head with the filter replacement. I assumed that cleaning the filter was a solution , but I read your reply and immediately went and bought a new filter . I will take your advice on checking all other lines and vents and then take it for a test ride as soon as possible . You will get a reply with the results .
jimh posted 05-18-2009 10:22 PM ET (US)
If any of your fuel lines are gray, check them carefully. Ethanol fuel has been known to damage these gray rubber lines. The liner of the hose separates and becomes very constricted, limited flow volume.

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Author	Topic: Yamaha 85-HP Starving for Gas
woodyh2006	posted 05-12-2009 07:15 AM ET (US) I have a RAGE 15 which has been converted to outboard drive from jet (with much help from continuousWave). It is a sweet little boat and suits the needs of my wife and myself, being trailerable to various campgrounds in our area. I have a 1994 Yamaha 85-HP motor which runs great at wide-open throttle and neutral idle, but has a problem with intermediate engine speeds with a load on the engine. I have had carb kits replaced, fuel pump replaced, spark plugs replaced, electronics checked, and I still have the same problem. I am living with this situation but another major problem is the motor runs smoothly when on plane turning anywhere from 3,500 to 5,500-RPM for about 15 minutes, and then shuts down to an idle, sucking the primer bulb flat. Thinking that it was picking up trash from a dirty built in fuel tank, I connected a new six-gallon tank with new line and primer bulb to the fuel-water separator, and got the same 15 minute run and then shut down. I have made sure the tank vents are open. I installed a brass tee in line prior to the fuel water separator with two ball valves so that I can run on either the built in-tank or the remote tank. By opening both valves thereby accessing both tanks it seems to run ok.This indicates to me that I have a vent problem. Are these two problems related?
jimh	posted 05-12-2009 09:05 AM ET (US) If the primer bulb goes flat, there is an obstruction upstream. Is the fuel-water filter upstream of the primer bulb? It sounds like the culprit.
woodyh2006	posted 05-12-2009 10:04 AM ET (US) Thanks for the reply . No , the fuel water filter is downstream of primer bulb on both tanks . I have checked and cleaned this filter as well as the screen filter on the engine . Both were clean .
boatn	posted 05-14-2009 05:21 PM ET (US) if there is not an obstruction in the tank I'd check the fuel line. Sometimes they age and the inside of the hose breaks down.
woodyh2006	posted 05-16-2009 02:48 PM ET (US) Hey thanks Boatn ,I just bought a new "premium " primer bulb and connecting fitting to the motor .I'll install these and replace the cheapy walmart bulb and connector. The fuel line is fairly new but I'll replace that as well .I try to burn midrange , no ethanol fuel but I don't have a source any more . I'll do a test run soon and let you know the result.
wezie	posted 05-17-2009 10:23 AM ET (US) There is most likely a screen on the end of the pick up tube, inside the tank. Do not forget to check that. It is small, but can be clogged. Good Luck
towboater	posted 05-17-2009 01:02 PM ET (US) As long as you are replacing the bulb, blow lots of air back thru the fuel lines into both tanks. This will guarantee both lines and the pickups are clear and the tanks are venting properly. If your vents are blocked, be ready to capture fuel coming back at you with a gas after you quit pumping air into the tank. If the gas doesnt come back at you, your tank is venting. Its a long shot, some of todays water separators are so efficient, fuel additives actually clog them up yet they look really good when you pull them off to inspect. Conjecture; The filter is clear enough to cover idle speed and WOT has enough pump pressure to by-pass? Yeah, I know, seems nuts. Just saying, replacing the filter will eliminate the issue. mk
woodyh2006	posted 05-18-2009 08:19 AM ET (US) I appreciate everyone's input. It has been very frustrating to take the boat out and encounter the same problem and have the outing turn sour . Towboater , I think that you hopefully hit the nail on the head with the filter replacement. I assumed that cleaning the filter was a solution , but I read your reply and immediately went and bought a new filter . I will take your advice on checking all other lines and vents and then take it for a test ride as soon as possible . You will get a reply with the results .
jimh	posted 05-18-2009 10:22 PM ET (US) If any of your fuel lines are gray, check them carefully. Ethanol fuel has been known to damage these gray rubber lines. The liner of the hose separates and becomes very constricted, limited flow volume.