Help 888 shuts doown when throttled up over 5 miles per hr

border · Nov 6, 2012

Hey guys, new to the forum. I have always had outboard engines but now have my first mercruiser. The problem I am having on its first trip out is when I idle out to the wake bouys and try to throttle up my boat it cuts out and dies instantly. I will add that it seems like its missing a little while going slow but runs great while out of water not under a load and will throttle all the way. I have read some threads on here about a shift interupter switch. Also this engine has an edlebrock intake and carb with a vaccume advance which I have heard its not supposed to have. also will the engine do this if the trim is all the way down?

Any help would be greatly appriciated, Thanks,

Justin

Another retired guy · Nov 6, 2012

Re: Help 888 shuts doown when throttled up over 5 miles per hr

Hi. This could be due to several things - but it's not because of the trim position or the shift interrupter switch ( you're already in gear ). Do you have any service history? It could be anything from bad fuel; restricted filters; Fuel pump/pressure; carb/choke adjustments; ignition etc.

llerrad · Nov 6, 2012

Re: Help 888 shuts doown when throttled up over 5 miles per hr

is this a 302?, check fuel lines clear from tank, how long since a tune up? points, cap etc. need more details about the engine condition.

grewvin1 · Nov 6, 2012

Re: Help 888 shuts doown when throttled up over 5 miles per hr

More engine info needed

border · Nov 6, 2012

Re: Help 888 shuts doown when throttled up over 5 miles per hr

Hey thanks guys for the responses. The motor is a 188 hp (stamp on valve cover) 302 I believe, all the fuel lines are brand new and the fuel cell is very clean, not sure how to test the pump pressure.

The engine is pretty clean and has over 110 psi at all cylinders. I am leaning toward ignition but not sure if I can replace it with parts from the auto parts store or not

Thanks again,
Justin

Another retired guy · Nov 6, 2012

Re: Help 888 shuts doown when throttled up over 5 miles per hr

border said:
Hey thanks guys for the responses. The motor is a 188 hp (stamp on valve cover) 302 I believe, all the fuel lines are brand new and the fuel cell is very clean, not sure how to test the pump pressure.

The engine is pretty clean and has over 110 psi at all cylinders. I am leaning toward ignition but not sure if I can replace it with parts from the auto parts store or not

Thanks again,
Justin

110 is a little low. You can use auto parts for plugs/wires/points but not the alternator.

border · Nov 6, 2012

Re: Help 888 shuts doown when throttled up over 5 miles per hr

I guessing you meant distributor, it was missing a little under load wondering if I just ask for points for a 74 302 I heard these 5 liters came with 351 heads, and don't know if that matters or not. I'm guessing on the fuel pump I would just run the hose to a can to see if its pumping well?

Another retired guy · Nov 6, 2012

Re: Help 888 shuts doown when throttled up over 5 miles per hr

border said:
I guessing you meant distributor, it was missing a little under load wondering if I just ask for points for a 74 302 I heard these 5 liters came with 351 heads, and don't know if that matters or not. I'm guessing on the fuel pump I would just run the hose to a can to see if its pumping well?

No, I meant alternator. The distributor parts can be/are the same as auto parts, but if you ever have to replace the alternator it has to be the marine version (spark protected).

dingdongs · Nov 6, 2012

Re: Help 888 shuts doown when throttled up over 5 miles per hr

points and timing needs correcting first and as you increase throttle the load increases so therefore fuel has to be increased to account for this.sounds as if the carb will require a strip down and clean of the small galleries.there is carb cleaner available so to soak it in but there is also the main fuel filter to address and also the small filterat the top of the carb before it goes through the float valve into the carb.chase the carb down and theres plenty of diy videos on youtube on how to rebuild a boats carb.

llerrad · Nov 6, 2012

Re: Help 888 shuts doown when throttled up over 5 miles per hr

you can get points, cap and cond. from any auto parts store. set points with 27 to 31 deg. dwell. for the cost put a cap on it get one with copper contacts not al. the coil could be craped. On my 302 i have had the same issue twice and both times I had a pug in the fuel line one at the tank elbow and the other from the fuel pump to the carb.

kmarine · Nov 6, 2012

Re: Help 888 shuts doown when throttled up over 5 miles per hr

could be sevral things. I would start with the carb. water in there will kill the engine as soon as you need more fuel than the idle jets can provide. Then make sure you have the correct distributor and ignition components working properly. most of the boats like yous that I see need carb work.

border · Nov 8, 2012

Re: Help 888 shuts doown when throttled up over 5 miles per hr

Thanks guys, I pulled the cap and everything's brand new on the distributer. I will do a carb tear down, timing/points check, and double check the fuel lines too. Thank you all, I'll post how it goes.

UncleWillie · Nov 8, 2012

Re: Help 888 shuts down when throttled up over 5 miles per hr

Re: Help 888 shuts down when throttled up over 5 miles per hr

If it cut out and dies instantly it is probably an ignition problem.
Fuel issues usually give at least a cough before they die.

Don't discount the wires and plugs and plug gap setting.
Plugs that can be fired in the open air or at low compression loads can fail to fire under higher loads.
Highly compressed air makes a tremendous insulator and needs a very high voltage to jump the spark plug gap.

Eric 3.7LX Alpha 1 · Nov 9, 2012

Re: Help 888 shuts down when throttled up over 5 miles per hr

Re: Help 888 shuts down when throttled up over 5 miles per hr

If you are going to do a tune up on it you can get the parts for a 888 right here at Iboats:
Mercruiser Tune Up Kits - iboats

what is the history of this boat? did you just pick it up or have it last season? Take it for a ride with the owner?

Check the Adults Only sticky at the beginning of this forum:

VV
http://forums.iboats.com/mercruiser...tdrives/adults-only-no-exceptions-288430.html

bubbahemi · Nov 16, 2012

Re: Help 888 shuts down when throttled up over 5 miles per hr

Re: Help 888 shuts down when throttled up over 5 miles per hr

it sounds like the carb

Help 888 shuts doown when throttled up over 5 miles per hr

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