1996 mercury 50hp force

[billhuey]

my 50hp force run great as long as the top is off the motor. when i put the top back on it chokes out and won't run. have had all new gaskets & etc. installed by a mechanic. He says he has done everything he knows to do but it still won't run with the top on!!! any help would be appreciated my wife is wanting to ride in the boat soon.<br />the motor runs wonderful with top on as long as it has the hose pipe on the motor.

 

[WillyBWright]

Re: 1996 mercury 50hp force

Welcome to iboats. <br /><br />I'll bet exhaust gasses are leaking into your hood. Find the source.

 

[JB]

Re: 1996 mercury 50hp force

Moving to Force Forum.

 

[roscoe]

Re: 1996 mercury 50hp force

Originally posted by sweetbaby:<br /> have had all new gaskets & etc. installed by a mechanic.

What gaskets & etc. ??<br /><br />Under the powerhead there is an adaptor plate, between the driveshaft housing and the powerhead. I would look there.<br /><br />The adaptor plate has 2 gaskets and a seal around the driveshaft. See your local Mercury dealer for these parts.<br /><br />As soon as you put the motor in the water, there is back pressure on the exhaust, and it is being forced up into the engine compartment.<br /><br />Numbers 2, 3, and 8 in this picture.<br /><br /><br />

 

[billhuey]

Re: 1996 mercury 50hp force

all i know is the mechanic said he replaced every gasket there was inside the motor. as you can see i know nothing about the motor!i am at the mechanics mercy!!!!!!

 

[steelespike]

Re: 1996 mercury 50hp force

As Roscoe says most likely these gaskets are leaking.Simply ask your mechanic to point out the gaskets he replaced.He either didn't get it right or missed a gasket.If he can't solve this common problem he is not a very good mechanic and you should look elsewhere.If you run the motor without the cover you may be able to find the leaky area between the powerhead and the leg just above the leg.It would have to be an area that is inside the cover when it is on.

 

[billhuey]

Re: 1996 mercury 50hp force

roscoe & spike, i took a print-out of the diagram you sent to the mechanic. he said he replaced 2,3,&8. is there anything else that will cause the leak? thanks for all your input!!!!!! If i run the motor with the hood off what am i looking for to finding the leak?

 

[WillyBWright]

Re: 1996 mercury 50hp force

This is a stretch, but I believe the air enters thru the hood at the handle on the back. I had a customer duct tape it shut to keep critters out over the winter. Had me scratching my head til I noticed it. He had forgotten about it.

 

[roscoe]

Re: 1996 mercury 50hp force

Does it run at all with the cover on?<br />If it is choking on exhaust gases, it should run for a minute or two, usually.<br /><br />I have also seen motors where the cover would push against a wire, causing it to flex just enough to push the wire against the engine causing it to ground out the ignition.

 

[billhuey]

Re: 1996 mercury 50hp force

thanks guys for all the help. been out of pocket and haven't been able to get anything done until today. put the top back on and it will run for a few minutes then quit. as long as top is off it runs great. this is in the water. also when out of the water hooked to the hose pipe the motor runs great with the top on. checked for a blockage but couldn't find anything.there's water coming into the bottom of the motor. it's not an awful lot. is this normal? now of all things the trim won't come up even tho it does go down. i'm almost to the point of dropping it in the lake. i have had it in 3 different places trying to get it fixed( same problem) the've all said they're stumped, they don't know what else to try!!!!!!!!!!!!

 

[roscoe]

Re: 1996 mercury 50hp force

Perhaps the exhaust port cover gaskets are leaking.<br />The exhaust port cover is the large flat cover on the side of the engine.<br />Ask the mechanic if he replace gaskets 12 and 14 in the picture below.<br /><br />Can you tell where the water is leaking from? Is it near this cover??<br /><br /><br />

 

[billhuey]

Re: 1996 mercury 50hp force

roscoe thanks for the tip. it's dark here so i'll have to wait until tommorow afternoon to check. i couldn't tell where the water is coming from but will take a closer look tomorrow. sure hope we can find whats wrong!!!!!!!!!!!!!!