Logo
FULL SITE MENU

80bs mercury 288 50L 8cyl engine NEWBIE questions

I

im4524

New member
"Just got the boat....Hopefull

"Just got the boat....Hopefully I identified the engine enough for you...Here are the question: Not sure if the first 2 are related to the third?

1. Blower motors...What are they suppose to do? I have. It appears that mine are not correct. SHould they BLOW or SUCK air from the engine compartment? Mine currently do neither. They were plugged.

2. On the outboard portoin, there is a rubber tube that has a big crack in it...I think it is the exhaust?(or could it be the water/cooling intake) Where could I find out the basics of how the cooling/exhaust flow?

3. Boat starts right up...idles good...in gear moves good up to about 2k RPM then starts to sputter/backfire. ALOT..will die if we don't throttle down. Doesn't matter if we move up slowly or gun it.

For issue 3, I thought the spark plug cables are on the wrong cylinders? but does not backfire at low RPM?

Lastly, anyone know a hint to test run the engine without it being in water....lake is a two hour drive?!?!"
 
"Get a factory set of manuals

"Get a factory set of manuals for the year of the engine and OD from eBay and read them.

1. Blower motors suck air out of the bilge and blow it out thru the air exhaust.

2. If it is on the bottom then it is exhaust.
The others need inspected and probably replaced.

3. It sounds like a fuel delivery issue. Change fuel filters. Plug wires are on correct. If the OD is an Alpha or older, buy a set of earmuffs and connect it to a garden hose and attach them to the bottom of the OD water inlets.

We are all glad to help you but w/all due respect, you sound like you need to read the manuals to learn how the engine and OD function together and you will be able to relate to information we provide you."
 
"Absolutely. Get the engine ma

"Absolutely. Get the engine manuals for drive and engine.
First thing I would do is a compression check and take note of the pressure on each cylinder. This way you will be sure to be sinking dollars into an engine that is worthy.
Once the integrity of the engine is established, I would start tuning her up.Oil and filter. Replace fuel filters, spark plugs, wires, distributor cap and rotor. Set timing. Check cooling system,replace thermostat. Make sure the oil and temp guage are working, check alarm, etc.

Service outdrive. Change gear Lube. Grease all points. Replace ALL seals and gaskets and o-rings.

That ought to get ya started!"
 
"Thanks for the responses...

"Thanks for the responses...
It is a mercury 8cyl 5.0 liter 288 engine. Is there another way to identify it?

1. Is a general manual for the year ok? I can't find one that says 288 on it?
2. PREVIOUS owner did a lot of work......some mistakes...as the air blower was totally wrong....basically..it sucked air in thru on exhaust vet and vented it out the other side....

3. Oil/filters all new. plugs/wires, distributer all new...have not checked timing my self yet. fluids all new...

4. I gotta question the wires being correct. Should they be in reverse order? They appear to be.

Thanks.."
 
"Model 288 does not compute.

"Model 288 does not compute.
How about model 228 maybe?
That was built from 1977-1983 using the 305 GM small block V-8.
If you want to know the actual year, refer to your boat hull SN. The last two digits are the year the boat was manufactured.

You need SM #4 for the engine and SM #6 for the drive.

Scroll down the last month or so of topics and look for one called "Ayuh; The back door is once again open"
That will take you to a site where you can download the pdf files for free. Courtesy Bondo.

Good luck.
Rod"
 
Just a update.
1. Blower moto

Just a update.
1. Blower motor is now wired(tubed) correctly.
2. The rubber exhaust tube on the outboard is replaced.

SN on boat is bwyma319 h788
Motor SN is 5581155
Motor is a 8 cyl. mercury 228. model mcm 228

Has a carb...the cover says 5.0L/LX Thunderbolt ignition. THere is a small gold 230 tag on it. The air filter is metalic gold about two inches high...does not look original(cover does not fit well).

Again well testing...runs decent at idle...when at about 2000 RPMS...starts to sputter/backfire...die....
Doesn't matter if you gun it or slowely get up to that point.

It has new distributor/wires/filters/fluids/plugs.....not sure on timing correctness yet..

Still should I look at the fuel?

Thanks
 
"I would change all fuel filte

"I would change all fuel filters as a minimum.
Check to see if there is a small porous media filter just inside the entrance fitting to the carb. This little guy plugs up very easily.

Should also check your timing, plugs, wires.
Check to make sure your choke is wide open once warmed up.

Rod"
 
George;
Looks like your boat

George;
Looks like your boat manufacturer does not follow standard boat SN patterns.
That engine SN falls into years 1979-82.

Rod
 
"[b]"Motor is a 8 cyl. mer

""Motor is a 8 cyl. mercury 228. model mcm 228"

Ayuh,... So it's a 305 Chevy,..

I'm thinking it's a 4bbl. Carb,... Are the secondaries opening,..??

"4. I gotta question the wires being correct. Should they be in reverse order?"

Nope,.... Nothing should be Reversed on that motor...

Rod,.. I'm thinking this Isn't an all original boat,..??..."
 
Bondo;
I'm thinking you a

Bondo;
I'm thinking you are right.
My book shows the 228 is definitely a 4 bbl carb; and to get 228 hp out of a 305 you would for sure need a 4 bbl. I am guessing that for those years it is very likely to be a Quadrajet.

Rod
 
"I know I said I would post pi

"I know I said I would post pics....but have not had a chance....Ok, where do I get "earmuffs"....what is the official name.....I would like to get cheaper ones...as the boat shop said they were 67.00....bass pro shop said they have them sometimes for 12.00....??
Any other suggestions..of is the price right?"
 
Any boat shop should have an a

Any boat shop should have an affordable set.
Get the type that has a heavy duty V shaped spring that squeezes them onto the drive leg.
You might also find them at NAPA or Autozone.
The band type with a velcro strap are a waste of time.

Rod
 
"Ok,

I got a set....hooked

"Ok,

I got a set....hooked it up...and started it...Runs great...no backfire...or loss of power up to 6000 RPM...does reverse fine too...

Only thing I noticed..should water flow thru the motor before I start it when the earmuffs are connected..it was no allowing it....

Where do I go next...did do the fuel filter/pump already...."
 
""Runs great...no backfire

""Runs great...no backfire...or loss of power up to 6000 RPM."

6000 RPMs on muffs...your engine doesn't like that one bit. Limit earmuff to 1500 RPMs.

"should water flow thru the motor before I start it when the earmuffs are connected"

No, the impeller is in the way.

"Where do I go next"

Take it for a spin on the water to see if it runs. If it still backfires, etc., perform what you have been advised by the members.

Did you clean the carb flame arrestor (cover)? If it is not original then it may be interfering with the carb linkages and throttles."
 
"Ok, Took it for a spin. at 10

"Ok, Took it for a spin. at 1000 RPM..fine...at 1900/2000 started to backfire like before...almost dies...Now..after running a hour..I was able to get up to 2400rpm before the backfire...Thoughts. I am thinking timing?"
 
Have you verified the secondar

Have you verified the secondaries and the choke are opening? Lack of sufficient fuel causes back firing. The mech. fuel pump filter been changed? Does the pump work?

"distributer all new...have not checked timing my self yet"

Connect a timing light and make sure that the base timing is correct and advances w/the RPMs. If not then I believe the Thunderbolt Amplifier Module controls advance--$400.
 
"Hey...got it runing great...s

"Hey...got it runing great...seems that it was 3 of the spark plug wires out of order....
Anyway, now the boat seems too heavy...really low in the back...sits deep in the water...When I gun it, I can barely see out even when I stand...



HELP???
}"
 
"Compliments of Rod Stewart

"Compliments of Rod Stewart

What prop is on the OD?

Get the boat weighed and subtract the trailer weight on the trailer title certificate.

Insert the boat weight, HP, elevation (feet above sea level), select boat type and it will tell you the prop it needs.

<center><table border=1><tr><td>http://www.marineengine.com/discus/icons/mime_msexcel.gif""" align=left alt=""application/vnd.ms-excel"">prop finder
[url=""][b]Copy of Copy_of_Boat_Speed_Finder-79780-193827.xls[/b][/url] (26.1 k)</td></tr></table></center>"
 
Back
Top