1994 225 twins sws 3.1lt V-76

[regulator express]

OK, sorry for the repost...it was getting confusing with two different engine problems.<br />Rodbolt, and others, thanks so very much for the advice earlier. <br /><br />I'll focus on the starboard engine in this post.<br />1994 engine originally 450 hrs, then in 2002 the previous owner got a brand new powerhead, fuel pumps, gears, oil pump, all redone and looks good. (he snapped a gear, then engine over-revved and blew) Owner said it ran great the first year after powerhead. But...he didn't use the boat more than 8 hours since then. AND, get this, he left it in the frozen canal both winters in 2002, 2003. In the last year, he said it doesn't run right, bogged badly. What a shock.<br /><br />I bought the boat this early summer. Put new gas in, new separators, and new primer bulb. Had my local outboard guy (excellent outboard mechanic, but not necessarily a yamaha specific guy) look both engines over and he adjusted carbs, and decarbed, and fixed a leaking oil and/or fuel hose. Also new plugs. Finally it at least idles decently, and can power up without stalling. (other engine runs good)<br /><br />In 2002 the tstats, sensors, and waterpump were new. This engine now suffers from weak power (missing slightly) on mid throttle, and no power at high throttle. In fact, pinned at WOT, it only reached 4400 rpm while the other engine gets up to 5300 no problem. <br /><br />I tried crossing the fuel lines, same problems. No water in any filters seen. I suspect a bad fuel pump (there are 3), or bad TPS. Symptoms seem like TPS, my mechanic thinks it might be carbs, I think it might be one fuel pump. I have the Clymer service manual, but it isn't the best with troubleshooting. Could this be just clogged jets in the carbs, bad pump, or TPS, or what? Also, the engine doesn't seem to rev higher on cold start like it's supposed to, (like other engine). <br /><br />Thanks guys, I NEED to go fishing soon. Can't thank you enough...I'll check this post many times a day until its fixed! Thanks

 

[regulator express]

Re: 1994 225 twins sws 3.1lt V-76

Is it true that I can test the fuel pumps by removing bolts connecting it to block, then squeeze the primer pulb, and fuel will pour out of a bad (ruptured) diapham? Or, do I have to buy the mightly vac tester? Or, (probably best) do like rodbolt advises and just replace em. <br /><br />My mechanic charges $95 per hour and he's very good, but should I clean/soak/blowout my carbs myself? Any special tools needed? <br /><br />Thanks.

 

[rodbolt]

Re: 1994 225 twins sws 3.1lt V-76

hello<br /> just change the pumps. its cheap insurance. a leaky diaphram can smoke a piston.<br /> and the cost of the pump is the same with or without pistons. you will need a diagnostic test lamp also known as the winky blinky to test for sensor failures. fuel is usually the problem though. you will need a test harness and a digital meter to reset the TPS voltage. there were some issues with some of the old TPS units. I would make sure the fuel system is up to par before jumpning on the electics. the system must be capeable of moving about 25 gallons of gas per hour at wot.<br /> you really need someone that is familiar with the V76 ign/fuel system and how it all works.<br /> good luck and keep posting

 

[regulator express]

Re: 1994 225 twins sws 3.1lt V-76

thanks rodbolt. much appreciated.<br />I guess I'll change the pumps even though they are only 2 years old. Labor is the expensive part, and I can change them for free.<br /><br />Being that I have 12 cylinders to take care of, I think I may try to learn to rebuild and clean the carburetors myself. If I ever buy that 1971 porsche 911 I've always wanted, I better learn how to rebuild carbs fast! lol! I have the clymer manual, and I'll get another, but I just hope I can do the job RIGHT myself and not have to get it done again by my mechanic. Maybe I'll let him do the carbs, and I'll work a few days on the weekend to pay for it. What should it cost?<br /><br />Thanks.

 

[rodbolt]

Re: 1994 225 twins sws 3.1lt V-76

the carbs are not hard just time consuming.<br /> all 6 are different so mark them and dissasemble and reassemble them one at a time<br />the3 fuel pumps you can change in 20 mins per engine. if the powerhead is not warming up the cold start will try to engage and drain the fuel from #6 fuel bowl.<br />good luck and keep posting<br /> PS the link and sync on thoise carbs are a bit tricky so dont trust just anyone