thermostat/choke issue?

bbr001256

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Apr 24, 2018
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2000 chaparral 205 sse. 5.0 liter mcm gm v-8, alpha 1 gen 2 outdrive. engine serial number 0L640839, transom serial number 0L835800

Bought this boat in feb 2018. The previous owner winterized it (antifreeze thru muffs and into thermostat housing). So after visually inspecting things i decided all was well last weekend and took boat out for first time on sat. It did not want to start/stay running but eventually it stayed running. The boat ran poorly from engine point of view. Stalling/hard starts/bogging/under revving/over revving/backfires or missing etc. So i phoned previous owner and he informed me he did not treat fuel when boat was shut down in oct 2017. So i topped tank off the next day with 93 octane, a can of sea foam, and some 104 octane booster. The engine improved the second time out. Missfired/bacfired ocassionaly and ran great @ wot. After researching ive learned the thermostat was never in the boat when the previous owner owned it. Now im assuming that the choke is probably staying closed (due to water temp send unit never telling electric choke to open due to water temp never reaching proper range?) which is partially the problem as to poor engine performance. I also assume at this point plugs are probably fouled and carb may need disassembled and cleaned/rebuilt. On a side note i have fair mechanical ability and this is MY FIRST BOAT. Thanks everybody.
 

Bondo

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Apr 17, 2002
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Ayuh,....... Welcome Aboard,........ Yer Assumin' an awful lot,.....

Go take the fuel filter off it, 'n dump it into a clear container,......
Then toss that filter, 'n install a new one,.....
After yer done, take a good look in the ole gas for Anything, but clean fresh gasoline,.....
Anything possibly in the carb, came through that filter,....
 

Maclin

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May 27, 2007
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6,761
The electric choke is heated by its' own internal coil and will open without much regard to outside influences, just fyi. If it is adjusted properly should not be an issue even without a thermostat.

The no thermostat bugs me though. Many times uninformed or lazy owners take it out to "solve" an overheating issue. Not good for the next guy (you)!), sorry.

Regarding the winterization method, Where are you located? Does it get real cold there?

Good luck!
 

bbr001256

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Apr 24, 2018
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bondo, new fuel filter on the way. thank you. maclin, i live in olney illinois. South western portion of the state. Home of the white squirrels. FYI.
 

nola mike

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Apr 22, 2009
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5,786
Maclin was asking because your boat doesn't sound like it was winterized properly, + cold weather = potentially bad things.
 

bbr001256

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Apr 24, 2018
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What i know thus far is the oil is clean/clear. The outdrive gear lube is clean/no water. I am certainly hoping that all continues to be well minus the gas/carb/thermostat issue i am currently experiencing. But i do know that persistence and good advice helps when one isnt sure. I will get to the bottom of it with the help of those who know. My plan for future winterizing is to follow the clymer manual to a t. Keep boat in the garage, put a block heater in the engine compartment. Thank you all in advance for reading and commenting.
 

QBhoy

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Mar 10, 2016
Messages
8,348
Ditch ALL of the fuel...new fuel filter and fresh fuel...you’ll need to clean carb out too.
May friend had the same issue.
He got lazy and only replaced filter...still popping.
Topped up fuel to max....still popping
cleaned carb...but better, but still popping and pre ignition run on after switching off
eventually ditched ALL fuel. Every drop...new filter and it’s spot on.
Someome on here mentioned that no matter how little contaminated fuel is left over (water) and no matter how much you top up...it remains contaminated and infects the fresh fuel. Octane numbers decrease and timing is affected. Causing miss fire and popping.
They were spot on.
 

bbr001256

Recruit
Joined
Apr 24, 2018
Messages
5
Changed fuel filter/thermostat today. ran good on the muffs but i will evacuate the fuel tank tmrw. run the tank of fuel on the new filter then change it again. thank you for your time/advice.
 

bbr001256

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Apr 24, 2018
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Update- had carb rebuilt, changed fuel filter(for the second time/fuel looked good), and the boat ran flawlessly. Thank you all for your time and input.
 
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