100 HP Newbie Questions.

[skyguy59]

Hi All, please bear with the newbie questions. I have just bought a 72 100 hp V4 Johnson. This is my first V4. I'm used to Mercs, The question I have is are these motors always cold natured. Mine starts and runs great,but takes forever to get warm. These things pump tons of water compared to a Merc. I know I shouldn't complain but it doesn't seem to want to idle very good until warm, I replaced the thermostat (vernatherm) and both springs. Didn't seem to help very much. I can't get it warm enough on the muffs to idle right. It wont idle much below 1100. Powerhead is just warm to the touch but not hot. After putting it in a barrel and running it for 30 to 45 min it will idle nicely at 650 in gear.I've also cleaned the carbs, new plugs and comp is 120-125 on all 4. Everything around the thermostat housing and valve seats looks new. This motor has never seen salt water and doesn't look like it has much time on it Is there something else I should check or is this the nature of the beast? (I haven't put it in the bay yet, just getting to know the motor first.)<br /><br />Thanks in advance<br /><br />Russ In S. Texas

 

[ledgefinder]

Re: 100 HP Newbie Questions.

Something's wierd there, it should warm right up. I'd double check the thermostat and venostat.<br /><br />Here's how the flows in that motor work. The thermostat 'dumps' water into the exhaust housing when the motor reaches operating temperature. Otherwise the water just circulates though the block, down to the pump, back up to block, etc.. When the thermostat does dump, the water pressure in the block drops, letting the venostat open and letting in cold water.<br /><br />The poor idle is not, IMHO, the nature of the beast. The 1969-72 BatteryCD V4s idle notably well even cold; both points-triggered and sensor-triggered (better than the 1973-77 models!).

 

[skyguy59]

Re: 100 HP Newbie Questions.

Thermostat, valves and springs are new. seats and housing look like new. I have been into the thermostat area three time to make sure I didn't have springs backwards etc. Carbs were cleaned in an ultrasound then had new kits put in them. What else can I check that could cause the idle problems. I am just guessing that the idle problems are caused by the engine running cold because it levels out after a bit.<br /><br />Russ In Texas

 

[Joe Reeves]

Re: 100 HP Newbie Questions.

When running on a flushette, a idle rpm of 1000 to 1100 is about right.<br /><br />The idle problem may be caused by ever so slightly clogged slow speed jets. Clean them out with a .028 drill.