I have a couple problems. I am not sure what year my engine is. The serial # is 6409099. when i look to buy parts do I look between 5600162 thru 0A904645 ( that says v-150 marathon). I know its a 150 hp just not sure the model. Secondly when I try to excel the the engine bogs down. when its in neutral I can race it as high as I like with no problem. Its just under strain she bogs down. I am assuming its fuel. Should I start there or am I completly off base. I was thinking fuel pump. I hate to go right to the carbs. everything I read says the carbs more often than not are usually not the problem and every always assumes they are (me included). any other trouble shooting ideas that I should look first?
Has it been sitting?
If so carbs could be the issue
If it just suddenly got this problem during regular use I would be looking at the ignition system.
Fuel pumps are a common trouble source, I replace diaphragm kits on my clients motors during annual maintenance.
They are cheap and you can't hurt yourself replacing the pump kit.
It was sitting for just a winter maybe two but when I winterize the engine I fog it then drain the fuel out of the carbs. Do you still think it might be the carbs. I have had troubles in the past with the iginition but it usually stalled and never started again.
Thanks for the info. I will do the fuel pump anyhow it could only help until i snap a bolt in the housing HAHA ( you know boats)
Carbs that old I would do kits,
Pretty easy except for the float settings. They can be a little tricky.
I would clean them with Mercury Power Tune, replace gaskets, floats, needles and reassemble without messing with the float adjustment 1st.
The floats are spring loaded on these carbs and they will flood if you squeeze the primer bulb too hard even when adjusted right.
I bought the kits and was ready to so battle when I noticed the the idle speed control assembly was disconnected. Could this be my problem before I rip apart the carbs? and either way where does it connected to on the engine.
well I did the carbs like suggested didnt mess with the floats they looked and sounded fine. I did find some gunk and one of the long thin nozzels clogged. I havnt tested it in the water yet but it idles and sound A LOT better than it did at idle and reving it ( when I thought it sounded good before). thanks for the advice.
One more question though ( if you dont mind) I replaced the water pump, cleaned out the popit valve and replace the thermostats with washers (removed the altogether). when the engine is at idle the tell is pumping great but when i put my hands on the heads the port one feels fine but the starboard on is getting hot to where i have to take my hand off it. any other ideas? It looks like the water goes through the port side first. the hose connecting the t-stats is clean.
old mariner engine
Linear Mode
