merc 90hp with issues

izuizme

Petty Officer 3rd Class
Joined
Jul 5, 2003
Messages
97
Its a 3cyl motor with oil injection,it runs fine untill I stop, and shut it down for a while to fish. I'll describe some concerns I have with this boat I recently brought. The motor normally starts up ok using the normal start proceedure, even though the primer bulb does not really firm up while pumping it.(brand new quicksilver bulb)Thats one issue the other is that after finishing a drift it does not always start right up,even though I know its still warm.I have to wait on it, and play around with it by depressing the key(enricher) lifting the fast idle lever,pumping the bulb.I can't figure out just what's at fault or how to fix it.I know that the fuel pump is brand new.I also noticed that the original quick disconnect fitting at the power head has been removed and replaced with a straight nipple, and the system has a cannister type fuel filter between the tank and the primer bulb.Hope this is enough information to help U guys figure out this problem.If U need photos of the setup I'll post them right away,just say the word..!!! :( :( :(
 

greasemonkeyozi

Petty Officer 1st Class
Joined
Jul 16, 2003
Messages
282
Re: merc 90hp with issues

If you cant really determine the problem why your motors not giving you your money's worth, I'll give you some pointers. First of all, is your motor still under warrenty? If not, lose the oil injector. Those things are noething but problems. Always feel safer when you manually mix your own fuel mixture.<br />You said that someone done some work and added a fuel filter, if so, change out the fuel filter. Possability it can be clogged or dirty. Also, check to see if the fuel line is taking on air somewhere. When I bought my motor, I saw that the manufacterers use zip ties on all fuel line ends, why, i dont know. I replaced those with screw tight hose clamps to ensure a good seal on the fuel line. Also, go ahead and replace that connector that hooks up the fuel line to your motor. Those things have a rubber O ring in it that will dryrott in time causing your fuel line to take on air.<br /> There is a possability that your fuel pump diaphram has a hole in it. You can buy a new kit to rebuild your fuel pump for only $5.00. Its a real easy and inexpensive task that should be done once every 3 years.<br /> Make sure you are getting spark to your plugs. Take one plug out at a time and hold it close to the motor while someone attempts to start the motor. Make sure each one is delevering good spark, if not, get back with us and tell us whats up.<br /> It wouldnt hurt to rebuild your carborators. There could also be a small piece of trash causing your jet to not be putting off enough fuel. You dont really have to buy a whole carb rebuild kit, all you need is new floats, new needle and seat, and a gasket set. This is really an easy job, you'd be suprised, just get back with us when you decide to rebuild them. For each carb, parts may run about $25.00 to $35.00. <br /> Before you take anything apart on your motor, try this real easy step. Go to NAPA and buy you a can of sea foam deep creep. take your spark plugs out and spray a good amount in each cylinder. put back together and let sit overnight to get all that carbon off your cylinders. Start motor next day and spray a good amount a little at a time in your carborators while motor is running. This is some pretty good stuff and is good for cleaning your system out, this may clear up your problem. I'm still arguing with other mechanics on this site about sea foam, some people dont think it does anything. Its like taking your car to have the fuel injectors cleaned or something. Try this stuff out and tell us what you think. All kinds of nasty stuff will blow out your exaust. I use this stuff with that technique every 3 tanks of fuel to keep my system cleaned out. <br />Good luck :D
 

The Marine Doctor

Commander
Joined
Jul 25, 2003
Messages
2,177
Re: merc 90hp with issues

If you have to use the choke to restart the engine..you have a problem with the low speed circuit of the carbs.<br /><br />Check for an air leak or like MGR said...look into rebuilding the carbs.<br /><br />TMD
 
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