40HP Merc loosing prime

[canadian_fisher]

I just purchased a previously enjoyed 1991 40HP Mercury with Remote Cointrols and TnT from a local dealer.<br />If I tilt the motor and fish for more than 10-15 minutes, the carbs leak out a pile of gas and I can barely get the motor started again.<br />To do so, I need to prime the bulb until tight, and normally it gets going. <br /><br />Question: Is this normal when I tilt, do I have an air leak somewhere, do I need a carb kit? <br /><br />Thanks

 

[Moody Blue]

Re: 40HP Merc loosing prime

Welcome to iboats c-f. Ive got the same year and motor but under the Mariner brand. Sounds like the carb floats need to be adjusted or the inlet needle is sticking open. Get a rebuild kit, disassemble and clean the carbs. Adjust the float levels as directed in the manual and reassemble. May as well rebuild the fuel pump at the same time it is so cheap and simple to do.

 

[canadian_fisher]

Re: 40HP Merc loosing prime

Thanks RodC.<br /><br />I quesses that was the solution but thought I would ask if anybody else had the same symptoms.<br />Carb and pump rebuild sounds like a nice 6-pack project this weekend.<br /><br />Cheers. CF

 

[Scali]

Re: 40HP Merc loosing prime

chances are Rod is right but I would run a strong concentrate of seafom/ gas mixture through it first.<br />I bet carbs are all gummed up from sitting & this sometimes does the job ..<br />Removing the carbs on this motor is a PIA { I have one too }.. try the easy route first

 

[canadian_fisher]

Re: 40HP Merc loosing prime

Agreed..... I will buy some de-carbonizer suggested by a local buddy. He also believes this might clear-up the starting issue.<br />I will ping back on the results.<br /><br />Cheers. CF

 

[Scali]

Re: 40HP Merc loosing prime

get the seafoam or other qualty brand that you add to the gas tank, clean out your tank add a gallon or 2 of gas & a heavy dose of seafoam then go blast around the bay or lake , then I'd do a power tune spray in carb deal let it soak good hour go blast aroungd again

 

[Wellcraft 89]

Re: 40HP Merc loosing prime

I would clean the carbs and rebuild.<br />Seafoam is fine for decarbing a engine that is running fine <br />But need to becareful after using it as cure for dirty carbs or gummy deposits in fuel system. <br />It can dislodge something that could get caught in a jet and when your blasting around the lake <br />lean out a cylinder and melt some pistons.<br />just be fore warned of possible problems from using.<br />Rich<br />Rich

 

[dynapac]

Re: 40HP Merc loosing prime

Rebuild the carbs. I agree with Wellcraft 89. I had gummed up carbs. Bottom bowl was full of varnish and gum. Poured a little Sea Foam in it to see what it did. Dissolved gunk real fast, but didn't liquefy it completely. I wondered if some of it could have plugged something up.

 

[Scali]

Re: 40HP Merc loosing prime

I got this from one of the Techs here on the site in recent post he mentioned go this route first & it has a high success rate.<br />edit, did a search for thread & couldnt find it it seems many people do think theres a {remote} risk of clogging a jet & leaning out the motor too much possibly melting a piston this way..<br />I'll add when I bought my new to me '94 40 HP last year the carb leaked & she sputtered a bit , I did this seafom treatment & motors run flawlessly put 100 hours on it to date..

 

[canadian_fisher]

Re: 40HP Merc loosing prime

Gentlemen.

Better late than never..........

Over the winter months, I pulled the hood and initiated the Carb overhaul.
Before getting that far, I had noticed that MANY of the fuel / oil lines had broken Tie-wraps. Most of them were very difficult to spot without try to wiggle them with a screw driver.
Changed about 12 fuel connections, and motor kicked over right away.......... doooohhhh.

Thanks folks. CF